What to do if I had mono back in june and my spleen was a bit enlarged. I am now having a lot of pain near my left back rib cage/ scapula area. Related?

Not related. Possible nerve impingement that can be caused by being sandwiched between two spinal bones, pressed by a bulging. It can cause muscle spasm and back pain. Prevention treatment is always recommended. See interventional pain management specialist for definitive diagnosis and management. .