The commonest cause of pain in the calf is DVT or deep vein thrombosis and clots. This is best diagnosed by duplex ultrasound (color dopplar) or by angiogram. Pain can also be felt post unaccustomed exercise due to muscle strain. A ripping pain in calf muscles can also be due to intermittent claudication. The diseased and thrombosed arteries go in spasm while walking or exercising, due to increased blood demand, there is reduced oxygen in muscles, and hence pain. Pain in the calf area can also be due to pinched spinal nerves in the lumbo-sacral area or a pinched nerve at the knee joint. A nerve conduction study should be done. A MRI of the lumbar spine should also be able to throw some light. A deep vein thrombophlebitis or intermittent claudication (spontaneous spasm and relaxation of arteries) can also cause similar symptoms. Infection of skin called cellulitis could also be a cause. It can also be infection of lymphatics. At times it is also due to low sodium, potassium, magnesium or calcium in the body. Hence serum levels of these electrolytes should also be checked. Dehydration is another frequent cause. Generalized weakness, increased weight, diabetic neuropathy, any peripheral neuropathy and severe anemia can all cause lower leg pains.
Do discuss this with your doctor and get yourself examined accordingly. You probably had dopplar ultrasound of the leg but other tests need to be done too Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.