A neck MRI will not likely show anything unless you have a more serious injury. The radiologists just do not look for the subtle issues common to concussions. But, you should stop cracking your neck, especially if they are painful. You could be doing harm. It can also cause inflammation that can make your symptoms worse. You should get a professional assessment of your neck. An upper cervical chiro can often help. They do very specialized X-Rays. Some Physical Therapists are good too. Avoid any aggressive therapy.

You should also get a post concussion vestibular assessment by a vestibular specialist, not a generic PT .

Read the Vitamins sticky (first post at the bottom) for the recipe to make some crushable ice packs and ice your neck as often as possible. 15 minutes on, 30 minutes off, repeat.

Sleep in a straight head and neck posture. If you have a recliner, it can be a good place to sleep with good posture because you cannot roll over and toss and turn.

Avoid potholes and jumping until your neck is healed.