Pain in shoulder does not go away could it be from lymphoma?

Possible,unlikely: If there is a history of lymphoma must r/o metastatic disease to shoulder itself. Seems unlikely but possible. Lymph nodes in the axilla can have a relationship.

Possible but: Lymphoma would not be the top of the list of causes of shoulder pain. Consider a sprain, bursitis, rotator cuff injury, neck pain , gallbladder problem for a right shoulder, and a host of other issues before lymphoma would come in for consideration.