Possible masseter muscle in cheek strain after dentist? 3 wk constant meds. Headache tooth pain ear pain. Wisd. Tooth RCT & 4 fillings. Cause of pain?

Inflammation. You may have an inflamed masseter from being stretched open too long or too wide; you could also have trismus from the anesthetic injection. Other possibilities include the occlusion being off on the new restorations. Moist heat, restricted diet and anti-inflammatories should resolve muscle pain; if the bite is off you need an occlusal adjustment.
See your dentist. The rule of thumb: all pains in the mouth and face to be of dental origin until proved otherwise. See your dentist for evaluation and treatment plan. Take care.
Wow. You've had a lot of work completed in a short period of time. The pain can be coming from any of the above procedures. Without knowing how deep the fillings were, if you were infected, or how difficult the extraction was, it's hard to say which might be the cause. Please see your dentist to determine what course of action is next on the list.
TMJ. More likely TMJ problem. See DDS. If agree see TMJ expert. See a TMJ expert to help evaluate and treat your problem. A TMJ expert can be general dentist, an oral surgeon, prosthodontist, orofacial pain specialist. Ask your physician, dentist or dental society for a recommendation.