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The normal heart rate
of a person is between 70-90/min and if you walk ;run or do work the heart beat increases so if the heart beat is 100/min after walking it is normal.The problem of swelling and pain in a single leg (left leg) is not normal also the breathing problem is not normal.Please get examined by a Physician and investigated immediately to rule out DVT(Deep Vein Thrombosis
).It can also be phlebitis
if it is red and inflammed or TAO
(thrombo angitic obliterance ) if you are a chronic smoker.Please write your age and better get investigated and treated.