The reasons are varied, but certainly we can acknowledge the unprecedented rate of change at every level of our society is one of the most important and obvious factors. It can bring up feelings of loss of control, dread, helplessness, hopelessness, feeling lost, confused, very afraid and angry. As the body internalizes these feelings, they can actually somatize into physical symptoms such as profuse sweating, heart palpitations, flushing, rashes, headaches and fatigue. People suffering from anxiety or panic attacks are sometimes convinced that they are experiencing a heart attack as the symptoms are so similar. If you are experiencing these symptoms you must first get them checked out by a doctor.
However, if you have been told that there is nothing wrong with you physically, then you need to deal with it on an emotional and psychological level.