There's a slight pain in my right underarm on touching which is otherwise unnoticeable. It occurs usually around my periods. The pain is similar to the sensitivity i feel in breasts while on periods. It is also visibly swollen compared to my left umderam. I am not sure what to get tested as i have already consulted a doctor who concluded it as muscular pain and gave me a few antibiotics but after the course there was no improvement. This started almost a year ago and im afraid whether it is a symptom of something serious.