I am a remicade patient and also take zoloft, (sertraline) methatrexate , and tramedol. i am now having pain and tenderness in rt armpit area.

See your doctor: Most likely you have swollen lymph nodes in the axilla. The reason for this should be explored. Less likely is a problem with the brachial plexus of nerves. A skin infection in the arm or hand can cause the regional lymph nodes to be swollen and tender. Being on Methotrexate i would definately have this problem looked at right away.