Stress can show up as just about anything. Upset stomach, back/neck/muscle spasms, tight chest, etc. Part of it depends on where you usually "hold" your tension. Personally, when I'm really stressed out it tends to affect the muscles in my shoulder blade/neck area. I hold a lot of tension there so it makes sense. The only thing for me that seems to work out the tension is stretching, exercise, and sleep. Oh, and breathing is big too. The most important thing to keep in mind is that your body is telling you something and you'd better listen or risk worse symptoms. If you can afford it, a good massage every now and then can work miracles and add years to your life. Just make sure you find a reputable physical therapist or massage place. I'd stay away from the ones that advertise a "happy ending," those'll probably drain your wallet but do little for your stress.