Is this dental/tooth issue or medical?

Hello, hope you are doing well. Looking at your OPG it seems that you have generalised attrition (wearing off of your teeth) which is most likely caused by grinding or clenching of teeth (known as bruxism). Also such a habit causes imbalanced and excessive forces in the joints of the lower jaw (Temporomandibular Joint) which may cause Temporomandibular Joint Disorder and later progress to degeneration of the joint (Degenerative Joint Disease). The TMJ on both the sides seem to have some changes which can be clarified by CT scan. Since you already have got CT scan done, it will be better to get a second opinion from another Oral and Maxillofacial Surgeon if possible to get it properly diagnosed and treated. But before that you need to get a night guard made to give your TMJ and surrounding muscles rest which will eventually give some relief from the pain. Also, the lump you are complaining of can be an enlarged lymph node which usually occurs when there is an infection in the facial region or oral cavity.

Hi, are your symptoms better now? Maybe this is unrelated but can be a cause of your symptoms, try considering the removal of 28, which is your upper left wisdom tooth, since it is supraerupted i.e. it has grown long because of the lower wisdom tooth not being there to stop its growth. As it is not in occlusion, it is acting as a point where your jaw closure is not correct resulting in your jaw moving forward or in a manner that is causing excessive pressure to the rest of your teeth resulting in grinding which has led to a widening on the fibres around your 27, and maybe 26 in the past which warranted the RCT in the first place.