You need to go back to your doctor to refer you for physiotherapy.
It does appear to be a muscular skeletal problem.
Perhaps your doctor could refer you to have an exray on your spine.
Have you been lifting or moving anything heavy and straining?
Do you feel any lumps in your armpit?
Take pain relief as recommended on the package and don't do any strenuous exercises or any lifting, pushing or pulling. Trapped nerves and muscle problems take a while to heal.
Gentle massage may help to relieve the tension in your muscles. Keep the area warm and out of any draughts.
Hi, Seeker! :-) Sorry, but we are not allowed to diagnose anything because we are not doctors. However we can suggest ideas for you to take to your doctor. You have lymph nodes in each armpit. Maybe the left one is 'being mean' for some reason. That is really why I wanted to respond to you, in case you hadn't considered that idea. Blessings - Blu
I don't feel any lumps around my armpits but yes I have been lifting weights twice a week for the last couple of months. I will stop and go to a doctor.
As you did not feeling any lumps around and under your armpits, you can rule out lymphatic problems.
Keep off the weight lifting and give your muscles and arm time to heal.
Glad to hear that you will stop the weight lifting and that you will be seeing your doctor again.
Let me know how you get on.