Could A Sore Neck Muscle Swelling Be MRSA Or Node Cancer?

I had a sore muscle feeling in my neck that gradually spread down to my shoulder, then to my arm and started into my side. I have also had a lymph node that has been swollen in my armpit for about 2 months. My doctor put me on antibotics saying he thought I had a staph infection. The 1st antibiotic, Cleocin stopped working after 7 days and I was getting worse and the soreness turned to pain. He switched me to Tetracycline and it too seemed to lose its effectivness after about 7 days. I have finished the Tetracycline and have developed constant pain in my neck and shoulder. My doctor has scheduled me to see a surgeon about a biopsy on my lymph node. But that's a week away just for the consultation and I am concerned about this pain. Is it possilbe I have MRSA or could this be related to cancer in the node?