*Web MD

#1: Worst Headache of Your Life

Get medical attention immediately. "If you have a cold, it could be a sinus headache," says Sandra Fryhofer, MD, MACP, spokeswoman for the American College of Physicians. "But you could have a brain hemorrhage or brain tumor. With any pain, unless you're sure of what caused it, get it checked out."

# 2: Pain or Discomfort in the Chest, Throat, Jaw, Shoulder, Arm, or Abdomen

Chest pain could be pneumoniaor a heart attack. But be aware that heart conditions typically appear as discomfort, not pain. "Don't wait for pain," says cardiologist Jerome Cohen, MD. "Heart patients talk about pressure. They'll clench their fist and put it over their chest or say it's like an elephant sitting on their chest." The discomfort associated with heart disease could also be in the upper chest, throat, jaw, left shoulder or arm, or abdomen and might be accompanied by nausea

# 3: Severe Abdominal Pain

Still have your appendix? Don't flirt with the possibility of a rupture. Gallbladder and pancreas problems, stomach ulcers, and intestinal blockages are some other possible causes of abdominal pain that need attention.

# 4: Calf Pain

One of the lesser known dangers is deep vein thrombosis (DVT), a blood clot that can occur in the leg's deep veins. It affects 2 million Americans a year, and it can be life-threatening. "The danger is that a piece of the clot could break loose and cause pulmonary embolism [a clot in the lungs], which could be fatal," says Fryhofer. Cancer, obesity, immobility due to prolonged bed rest or long-distance travel, pregnancy, and advanced age are among the risk factors.

# 5: Burning Feet or Legs

Nearly one-third of the 20 million Americans who have diabetes are undiagnosed, according to the American Diabetes Association. "In some people who don't know they have diabetes, peripheral neuropathy could be one of the first signs," says Brangman. "It's a burning or pins-and-needles sensation in the feet or legs that can indicate nerve damage."