TMJ... Bite alignment?

There is obviously something not right in your temporomandibular joint(TMJ). Conventional x-rays may not show the problem. If you were a patient of mine I would ask for a 3D CT (i CAT) scan and MRI. The CT will show hard tissue the MRI soft tissue, mainly the cartilage disc your jaw articulates on. I suspect you may have a displaced disc, this can best be determined with these scans read by a radiologist. The muscle relaxants can help, but you need to find out what the actual problem causing this is and have it treated. Bioesthetic dentists have this training and would be a great resource to consult. A list can be found at the link below.