I was doing regular jog for about 6-7 KM for two weeks. One day decided to do interval training and started running fast. After about 400m my left lower leg started to hurt. I continued slow run for another half a KM. Since then I cannot run as my left lower leg starts paining within 100 m. I believe it is shin splint. I have been resting since then. Wearing a crepe bandage to support my lower leg. It has been 15 days. How long does it take to heal. By lower leg I mean, front part of the calf.
Like others have suggested, you need to see a medical person, I would suggest a physio or osteopath.
I think it is unlikely to be shin splints, and more likely to be chronic compartment syndrome. http://orthoinfo.aaos.org/topic.cfm?topic=a00204 This is when you increase exercise volume and the muscles grows faster than the muscle facia. It can be extremely painful. But the good news is you can recover much quicker than from shin splints. A series of very deep massage, will help a lot. An Osteopath really helped with mine. This is not to be confused with acute compartment syndrome which is a medical emergency. See the above link for a better explanation. I have a lot of running/run coaching experience, but I'm not medically trained, so please do get some expert advice.