Even if i run for a minute or two, the lower portion of my leg (from ankle to the knee) starts paining severely. the pain persists for several weeks.

Shin splints: You might be describing shin splints (http://www.Mayoclinic.Com/health/shin-splints/ds00271). Rest & ice are key. I don't know about india but here in the states, you can get Acetaminophen & Ibuprofen over-the-counter w/o prescription. More importantly, if this persists, go see your family doctor for examination. I can only hazard a guess based upon 2 sentences half a world away.

Shin Splints!: Sounds like you may be having shin splints. Here are some helpful things you can do: rest your body. Ice your shin to ease pain and swelling. Anti-inflammatory painkillers. Nonsteroidal anti-inflammatory drugs will help with pain and swelling. Arch supports for your shoes. Range-of-motion exercises. Neoprene sleeve to support and warm your leg. Physical therapy to strengthen the muscles in shin.