? 
Pend Ding, I am not a doctor, but the following info can be helpful.
Your problem could be just the muscle pain, but watch out for heart attack warning signs. How old are you? You can find tons of information on the web. Follow this link:
http://www.americanheart.org/presenter.jhtml?identifier=3053#Heart_Attack
Another link.
Am I having a heart attack?
The chest pain or discomfort that you feel during a heart attack may be very similar to what you feel during an episode of angina. In many cases, however, there are important differences. The table below summarizes these differences.
|
Characteristic of symptom |
Angina |
Heart attack |
|---|---|---|
| How long chest pain lasts | Less than 5 minutes | 5 minutes or longer |
| Consistency of chest pain | Comes and goes | Constant |
| How bad the chest pain is | Less intense | More intense |
| Other symptoms, such as nausea, sweating, or difficulty breathing | Less likely | More likely |
| Resolves with medication (nitroglycerin) or rest | Yes | No |
Although the pain of a heart attack is usually severe, it can vary greatly. In fact, some heart attacks are never recognized (silent infarctions) because the symptoms are mild, not typical, or even absent. This is a major reason why some people don't come to the hospital when they have a heart attack. If you have angina and notice that it is happening more often or lasting longer, you should contact your doctor.