How to treat leg pain that happened because doing much exercise on first day ?

Leg pain: Give the leg a little rest. Consider using stream of warm water (like a shower or jets from a hot tub) on the areas that are sore. Tylenol can also help if you find other methods to be inadequate. Return to gentle streching. Stretch before any exercise routine and stretch after as well. Use common sense as far as pacing your physical activity. Take care.