Brief Answer:
muscle spasm

Detailed Answer:
Hello

Thanks for the query

It looks like you have spasm of the muscles that attach to collar bone. It is most often due to abnormal position while sleeping

Here is what you should do
1. Do not try to touch or stretch your neck muscles
2. avoid exercises until you are better
3. Tab acetaminophen is a good pain killer so it ibuprofen. Take one now after food
4. Apply cold packs on the painful area for immediate relief from the pain. Apply it three to four times a day

I hope I was of help, if you have any further queries please get back to me

Regards

---