Calf pain is a very common problem seen among athletes; the very basic reason in most scenarios is overuse of the muscles. There are other reasons for calf pain like blood clots in the deep veins of the leg causing blockage of blood circulation, collection of knee joint fluid in the back of the knee called as Wikipedia reference-linkbaker's cyst, blockage of blood circulation caused due to blood clots in the veins, Soleus pain caused due to the soleus muscle strain and Achilles tenditis caused due to the strain on the Achilles tendons. The only conclusion I could end up to after going through the information provided by you is soleus muscle strain which at times can add to the pressure on the knee. Using a good massager on a regular basis is a good way of getting rid from these problems. I would recommend OSIM uSqueez warm, a calf massager with great features like warm air technology which helps improve blood circulation, wrap around and squeeze to deliver a simultaneous massage to feet, calves and ankles and inbuilt foot rollers to deliver a foot reflexology massage which helps alleviates muscle aches by stimulating all the vital acupressure points.