Hello I appreciate your concern Tightness in calf muscles which lasts for 20 minutes could be related to muscle spasm or deep vein thrombosis I would like further information to help you better Your age and complete medical history Do you smoke? Is it associated with intense pain? Any aggravating or relieving factor if you could identify any it needs to be examined physically for swelling or tenderness, so in my opinion you should consult your doctor for examination and battery of tests like blood coagulation profile for confirmation of diagnosis Meanwhile you can take multivitamin especially vitamin B 12 and calcium supplements Bed rest until Diagnosis confirms Hope this helps you Best wishes