What is the treatment for TIA, intermittent headache, and stiffness in the neck?

Hi doctor,

I am a 27-year-old male taking 20 mg of Atorvastatin and 81 mg of Aspirin daily. I was diagnosed with a TIA two years ago. The TIA was diagnosed based on my symptoms; no clear cause was found. I am trying to determine whether I have a pinched nerve or cervical artery dissection. I had intermittent headaches on the back, right side of my head, and above my ear. I had no other pain, and the headaches would go away quickly and then return. I would not consider them severe, but they were uncomfortable, and I have never had headaches in the back of my head. The next day, I developed pain on the left side of my neck as the headaches on the right side of my head lessened significantly. And after that, the headaches on my right side were gone, but the pain and stiffness in my neck got worsened. I had some shooting numbness down my left arm. After that, the numbness in my left arm was gone, but the pain in my neck was still there. It was typically in the same spot on the left back side of my neck, but the stiffness of my entire neck sometimes happens. There is not always a pain as it comes and goes. I can turn my head from left to right without too much pain. Today, the pain and stiffness were mainly in my neck, and I started having intermittent headaches on the back left side of my head. I have pinched a nerve in my neck each of the past two summers, but the pain was mainly in my shoulder blade and would extend to the neck, but it never produced any headaches. I think it is likely just a pinched nerve, but I read some articles online about cervical artery dissection, which have scared me a bit.

Thanks.