Severe headaches and neck pains

About a yea and a half ago, I went in to see my doctor about these intense headaches I was having. At first, it would feel like muscle tension in my left shoulder that would send shooting pains up through the side of my head, causing pains in my jawbone and up the back/left sides of my head. My doctor ruled it out as muscle tension headaches as in only lasted a couple of days and prescribed cyclobenzaprine which I was told I could take with Aleve if necessary.

A little over a week ago, was started out as the same type of headache, turned into a week long pain marathon of not only intolerable neck and head pains, but also led to shooting pains from my shoulder socket all the way to my mid-forearm. My pinky finger and ring finger get tingly, almost to the point of numbness and, at one point, I was having throbbing muscle pains and soreness through the LEFT side of my body that were so severe I was unable to turn my body or neck. The only thing that was keeping the pain at bay was an on-going re-fueling of vicodin amout every 5 hours for quite a few days. I went to the doctor as soon as I could manage to move and after basic neurological tests, was sent in for an MRI of my brain. The MRI came back completely healthy& normal with no signs of trauma, tumors or concerns of any kind.

I am going in for physical therapy to see if I can learn how to relax my LEFT shoulder muscles, but even after a week of tests and vicodin, the pain is still living strong. Even my doctor agrees that the symptoms are a bit extreme for just having muscle tension headaches but many of the tests just come out as "healthy." If anyone may have any insight or experience with these symptoms, please let me know! It is only on the left side and creates headaches that are difficult to withstand sans medication. I am only 21 and do not want to be on chronic pain medications and have never had any trauma or major injuries to any part of my body. I eat healthy, keep myself in good shape and don't drugs.

Any insight would help!

Thanks in advance