5 days ago, I was carrying a heavy backpack and felt onset of neck pain (maybe a pinched nerve). It went away and 2 days ago I noticed the pain (more on left back side) in addition to pain in the back of my head on left side. There is a small area that is tender to the touch (like a bruise). I haven't hit my head on anything recently to cause a bruise. The neck pain has subsided but the area in the back of the head has not. Initially, I noticed the head pain when I turned my head to the side. Now it seems to be coming and going over past two days. The sore area does not appear to be raised or swollen. Not sure what this might be. I've taken 2-200mg ibuprofen tablets in past two days and this seemed to help yesterday. Today, not so much. Thoughts on what I should consider the problem or source?