Leg pain is a common condition. However, in a young person this is not a normal condition. Specifically, pain in the calf can be problem. I would strongly recommend that you see your doctors
">primary care doctor in order to have this evaluated.
In general, there are a few causes of pain in the calf. The one that many doctors worry
about is a deep vein thrombosis, or DVT as its known. DVT is a clot in the vein of the leg -- the vessel that returns blood from the foot to the heart. A clot in the leg can cause pain and swelling in the leg. This is a major concern because if the clot breaks off from the leg, it can travel to the heart and subsequently go the the lung. This can cause shortness of breath and chest pain and in severe cases death. This should be evaluated.
Other causes of calf pain could be a ruptured Baker's Cyst. A Baker's cyst is a collection of fluid behind the knee that lubricates the knee. If it ruptures it can cause severe calf pain.
Other causes include inflammation of the muscles in the calf -- namely the gastrocnemius and soleus muscle. This is often self healing but could represent a widespread disease.
Talk to your primary care doctor.