Trigger point injections are a treatment for myofascial pain, where a clinician inserts a small needle directly into a muscle “knot” and injects a local anesthetic to release it. The procedure takes only a few minutes, can be done in a regular office visit, and typically provides relief lasting several weeks to several months. It’s one of the most common in-office treatments for chronic muscle pain that hasn’t responded to massage, stretching, or over-the-counter pain relievers.
What Trigger Points Are
A trigger point is a tight, irritable band within a muscle that won’t relax on its own. You can sometimes feel it as a small, hard knot under the skin. What makes trigger points different from ordinary muscle soreness is that they often send pain to other areas of the body. A trigger point in your trapezius muscle (the large muscle spanning your upper back and neck) can cause tension headaches. A trigger point in the piriformis muscle deep in your buttock can press on the sciatic nerve, causing pain that radiates down your leg.
Trigger points develop from muscle overuse, poor posture, injury, or stress. They can persist for months or years, creating a cycle where the tight muscle restricts blood flow to the area, which prevents the tissue from healing, which keeps the muscle tight. When physical therapy, stretching, and other conservative treatments don’t break this cycle, injections become a practical next step.
Conditions Trigger Point Injections Treat
The most common reason people get these injections is myofascial pain syndrome, a condition defined by chronic pain originating from trigger points. But the list of conditions that respond to this treatment is broader than many people expect:
- Tension headaches caused by trigger points in the neck and upper back muscles
- Fibromyalgia, where widespread muscle tenderness includes identifiable trigger points
- Piriformis syndrome, where a tight piriformis muscle compresses the sciatic nerve
- Low back pain originating from trigger points in the lumbar or gluteal muscles
- Jaw pain (TMJ disorders) involving the muscles of mastication
- Shoulder and neck pain from desk work, repetitive strain, or postural imbalances
What’s in the Injection
Most trigger point injections contain a local anesthetic, the same type of numbing agent used in dental procedures. Lidocaine and bupivacaine are the two most common choices. Lidocaine acts quickly but wears off sooner, while bupivacaine takes a bit longer to kick in but provides longer-lasting numbness. Some clinicians add a corticosteroid to the injection to reduce inflammation around the trigger point, though this isn’t always necessary.
In some cases, clinicians use “dry needling,” where the needle is inserted without any medication at all. The mechanical disruption of the needle itself can be enough to break up the trigger point and release the taut muscle band. Dry needling is a legitimate alternative, particularly for patients who are sensitive to anesthetics, though most providers prefer using a small amount of local anesthetic for patient comfort.
What the Procedure Feels Like
The clinician starts by feeling for the trigger point with their fingers, pressing along the tight muscle band until they locate the point of maximum tenderness. Pressing on an active trigger point often produces a “jump sign,” an involuntary flinch, which confirms the right spot. They then pinch the trigger point between their fingers to hold it in place so it doesn’t roll away from the needle.
After cleaning the skin with alcohol, the clinician inserts a thin needle about 1 to 2 centimeters away from the trigger point and advances it at a shallow angle. You’ll likely feel a brief, sharp pain or a muscle twitch as the needle reaches the knot. This twitch response is actually a good sign. It means the needle has hit the trigger point directly. A small amount of anesthetic (as little as 0.2 milliliters) is injected, then the clinician redirects the needle in several directions, fanning through the trigger point to break up the entire taut band. The whole process typically takes less than five minutes per trigger point.
Most people describe the sensation as a deep ache or cramping that lasts only seconds. The local anesthetic begins working almost immediately, and many patients feel significant relief before they leave the office.
How Long Relief Lasts
Relief from a single trigger point injection typically lasts at least four weeks and often several months. The range varies widely depending on the underlying cause, how long the trigger point has been active, and whether you address the factors that created it in the first place. Someone who gets an injection for a trigger point caused by a temporary overuse injury may never need another one. Someone with chronic postural issues or a repetitive job may need periodic treatments.
Guidelines from pain management specialists recommend that during an initial treatment phase, injections can be given as frequently as weekly to get pain under control, but no more than four sessions during this diagnostic period. After that, injections should be spaced at least two months apart. The general ceiling is six injections per year for ongoing management. Medicare coverage guidelines limit reimbursement to three sessions per rolling 12-month period, so insurance coverage may be more restrictive than the clinical maximum.
For the injections to provide lasting benefit, each treatment should produce at least 50% pain improvement that holds for a minimum of six weeks. If you’re not hitting that threshold, your provider will likely reassess whether trigger point injections are the right approach for your particular pain.
Risks and Side Effects
Trigger point injections are considered low-risk. The most common side effects are soreness or bruising at the injection site, which typically resolves within a day or two. Some people experience temporary numbness in the area from the anesthetic, which wears off within a few hours.
Rare but more serious complications depend on where the injection is given. Injections near the chest wall (for upper back or shoulder trigger points) carry a small risk of puncturing the lung lining, a condition called pneumothorax. This is uncommon in experienced hands but is one reason these injections should be performed by a trained provider. Infection at the injection site is possible but rare with proper sterile technique. Allergic reactions to the anesthetic can occur but are uncommon.
It’s generally not considered safe or effective to inject multiple muscle groups in different anatomical regions during the same session, or to combine trigger point injections with other types of nerve blocks (like epidural steroid injections) on the same day.
What to Do After the Injection
You can usually return to normal activities the same day. Many clinicians recommend gentle stretching of the treated muscle in the hours and days following the injection to take advantage of the newly relaxed tissue. Applying ice to the injection site for 15 to 20 minutes can help with any post-injection soreness. Heat may also be used after the first day to promote blood flow and healing.
The injection works best as part of a broader plan. If the trigger point developed because of poor ergonomics, repetitive movements, or muscle weakness, those underlying issues need to be addressed to prevent the knot from returning. Physical therapy, postural correction, regular stretching, and stress management all improve the long-term success of trigger point injections. Without these complementary steps, trigger points tend to recur in the same location.