Thanks for posting your query,
Amtas M 50mg contains the drugs with generic names amlodipine
5mg and metoprolol
tartrate 50mg and usually control of high blood pressure
is usually started with a single drug therapy and if that does not work, either the drug dosage is increased (to maximum allowed dose) or another antihypertensive drug (from another class) is added (up to 4-5 different classes). Your doctor simply added metoprolol to your initial amlo 5mg (amlodipine 5mg) and targeted the control of your fast heart rate/pulse with metoprolol. Now one of the side effects of metoprolol is chain pain and that will require that you call your doctor as soon as possible as that is considered a serious side effect.
So call your doctor now, there might a possible change of drug regimen.
Hope this helps and wish you the best