The best I can offer is to ask you to see your doctor. Most likely, there's nothing wrong physically, but it's always best to find out. Also, if the doctor does find something, he can start treating it before it becomes something major. Perhaps you should take a good look at your life, and try to see if there have been any major changes, or anything that has caused an incress in your level of stress. Stress, caffein, and alcohol are the common things to look for as causes if nothing physical is found.