I Have Been Getting Severe Pain In My Left Side

I have been getting severe pain in my left side under my arm. It also hurts under my left shoulder blade sometimes as well. It usually is only when I sleep on my left side, but today it has been hurting during the day. I changed to sleeping on my right side which has helped the last two nights. I did have the same pain a couple months ago on both sides for about two weeks which made it almost impossible to get a breath when I would get out of bed. It then went away until about three weeks ago until It returned. I am not sure it has anything to do with it but I have several back issues such as several bulged disk, spinal stenosis, both in Cervical, Thoracic, Lumbar. Sacral aread. I also a spinal cord stimulator because I have Arachnoiditis in my Lumbar, Sacral, and Coccyx areas. Thank you, Alvin Bledsoe,