SCM muscle larger on one side of neck
About 3 months ago out of the blue one day i started having a tingly sensation in my left shoulder. Then i started noticing the left side of my neck when i would bend it to the right was really tight and it would hurt to try to stretch it. Also when i "flex" my neck the left side can't move as much as the right from where its so tight i guess. Within a few weeks the tingly pain turned into sharp and numbing pain going from my neck down to my fingers all on the left side. Also ended up having a major tension headache that sent me to the ER where they did a CT scan on head and said everything in there looked good. Went to the DR multiple times and even an ENT because i started experiencing problems with my jaw locking on that side and my ear on that side being stuffy and everytime they would feel my neck they didn't feel any lumps, just tight muscles. Also had a xray done of the cervical spine and shoulder. This was causing me major anxiety because it seemed like that side of my body was always in pain and i started to pay more attention and my SCM muscle on the left side of my neck looks larger than the right and it almost looks swollen. This whole time i was starting to have panic attacks because i was scared it could be something like a gland in there swelling or cancer but every dr says it doesn't feel like that but a muscle issue. I went last week under everyones recommendations to get a massage and the lady did alot of trigger point stuff and it seemed to make it worse but now 5 days later my ear isn't stuffy anymore and my jaw has quit popping. My muscle on that side still looks bigger and puffy but that area doesnt feel tight like it did before. Has anyone else ever had problem with that muscle and if so what can cause this paticular muscle to do this? At the time i had taken up running so idk if thats whaat caused it or if it was just a coicidence.
*Also for about 3 weeks now the pain in my arm and down to my fingers is finally gone but my shoudler does feel stiff and weaker on that side.