In my opinion, you should probably have an MRI of your neck (cervical spine). Though I haven't had one yet either, I get horrible neck pain flares sometimes, with pain that radiates to my left shoulder. Sometimes it goes into my arms as well. I can't turn or nod my head and I get a throbbing pain inside my neck in one area. Then I get the shoulder pain, plus sometimes some extreme shoulder spasms, where my shoulder is actually pushed forward and feels out of place. And when I coughed, I would feel pain in my arm. And when my neck flares up, the pain & achiness makes it feel like my head is way too heavy for my neck. Like I feel like I need to take my head, it's alot of pressure, feels like my whole neck area is being compressed. So perhaps that might be similar to what you described? Then it hurts to even wear a bra. Then I will get a headache that goes from my neck and up the back of my head, then it spreads into my jaw area and my jaw starts cramping up. I've also had the spasms spread to my throat and face. I am pretty sure that I have neck arthritis and probably have had disk compression or some sort of compression in my neck when these flares happen.
I also have problems with my fingers going numb, sometimes it's my entire hands. And i've also woken up (sleeping on my back) with both arms dead, completely numb. You should see the way I have to sleep now, but it definitely helps my neck. My upper body is propped up on several pilllows, and my head rests on a U-shaped cervical pillow. It's when I was more flat that my arms would go numb more often. Especially since you mentioned you were a cheerleader, it would make sense that you might have some degeneration or disk problems in your neck now.....so if PT doesn't help at all, I would try to get a neck MRI done to investigate further.