4. Tension In The Muscles:
If there is too much tension in the pectoral, triceps, or latissimus dorsi muscles or if these muscles are torn in excess, there may be severe pain in your arm. Although there is no specific muscle in the armpit, the pain of the surrounding muscles can spread to this place, said Dr. Allen. If you take a rest, this pain will go away. At this time you can take ibuprofen to get rid of the pain.