At the crag or on a multi-pitch route, there's pretty much no way out of having to belay. And unless you're using the mirrored belay glasses, or your partner is climbing very, very low angle slab, you're going to be looking up for extended periods of time. Personally, I consider about 2 minutes to be “extended periods of time”.
Your partner starts out, and by the time they have either placed the first piece of gear, or clipped the second bolt, your neck is already screaming and you're dying to look down. This is part of climbing. You cannot take your eyes off of your ever-ascending partner, and you can't take your hands off of the rope to tend to the aching muscles on the back of your neck. What I'm telling you is what you already knew: deal with it.
After you hear the “off belay” you've been dying to hear, you can look down and tend to the sore, cramped muscles on the back of your neck. Here's a few tips on how to relieve the discomfort in your neck after you have belayed, either on-site, or at home:
Look down: As you look up, the muscles in the back of your neck and mostly at the base of your skull will become cramped from extended contraction. To alleviate this, stretch them by looking down and tucking your chin to your chest. I also like what I call the “smell your armpit” stretch. Put your nose into your armpit, and using your hand on that armpit side, pull your head down with only the weight of your arm. This will address tightness in the armpit-opposite upper trap muscle.
Self-massage: This can most easily be accomplished by rubbing out the sore muscles with your hands. It helps at the crag or on-route, but what more can you do at home? I like to take two tennis balls and put them into a sock tying a knot at the top so that the balls cannot be separated in the sock. Lie on your back and place the two balls at the muscles near the base of your skull and top of your neck. Just let the weight of your head rest on the balls. This will create a pressure that relieves any muscle knots as you lay on it. It helps to lie on the floor, and you may need to add some folded towels under the balls to raise them higher to create the desired pressure.
Chiropractic: For more serious and/or persistent neck pain, you might have more than just muscle tightness. A visit to your chiropractic physician can check for dysfunction in the joints of the neck. This dysfunction can often be relieved with chiropractic manipulative therapy.
Belay glasses: There are now several brands of these available for purchase. They use mirrors so that you can keep your head straight, but your gaze up on your partner. Practice wearing them and getting used to the view through them before having your friend jump on their project—it takes a little getting used to.
Boulder: Don't want to look up and belay? Start bouldering. You will have a 30 second spot, max. All you need is some crash pads, crazy strength, and a beanie!
If you have pain or discomfort in your neck from climbing or other sports/activities, please do not hesitate to contact Dr. Stoughton at Evergreen Spine & Sports Medicine by phone at 303-670-8902 or email at firstname.lastname@example.org.