Have a pain over my left breast that comes and goes?

Evaluate if breast,: pain could be in muscle,should check to see any mass in breast, get checked to make sure not heart or lung problem.

Usually muscle: probably worth an EKG and an exam to rule out referred cardiac pain.

Difficult to answer: Intermittent left chest pain is often due to muscle strain. A physician would need to examine the area and find out how long you've had this problem, its severity, what brings it on and what relieves it in order to see if that is the diagnosis for your pain. Please see your physician if the pain persists.