This appears just to be muscular spasm or due to accumulation of lactic acid. All that you need to do is not to exert at a stretch for some days. Have massage
of calf muscles with sesame oil or vishgarbh tail if you can get it. Internally you can have tab. myostaal 2 bd. Application of heat with hot water bottle at bed time will help to relieve spasm and also to displace lactic acid accumulation.