The popping sounds suggest spinal degenerative changes, or weakening of the joint capsules. I'd suspect an upper cervical misalignment -- there are doctors within the chiropractic profession who focus exclusively on this region of the spine. Take a look at www.UpCspine.com and sift through their referral directory. Visiting an Upper Cervical chiropractor, in my opinion, is a smart thing to do.
I see my chiropractor for everything...everything. If he feels it is something that should be treated by a family doctor or another type of doctor he will refer me...which he has only done once when I somehow managed to tangle with poison ivy. He told me I needed to take a steroid to knock down the reaction & told me to go see my family doctor...I did this & a week later I was better. Also, when I am getting regular adjustments I dont catch alot of the colds that are going around...its great. I actually started seeing my chiropractor about a year and a half after a car accident that injured my back & the ER doctor along with my family doctor had NO CLUE how to fix. It was the worst year & a half of my life...pain & constantly thinking something serious was wrong with me because of all of the useless tests my family doctor decided to run. My family doctor ordered blood tests, X-rays, EKG's, and a ton of other test I cant even remember. He had me convinced something was wrong with either my heart or lungs. It turned out it was just that the ER doctor didnt catch an injury to my spine & therefore didnt treat it which resulted in it not healing properly. Over the course of about 6 months the chiropractor was able to fix what had taken my family doctor a year & a half just to diagnose. I say go see a chiropractor. :)