Muscle cramps. Cramping & stiffness.

Muscle cramping is usually sign of compensation. Which means that a muscle goes into cramping when it actually compensates by contracting ( working) more for another area weakness. Lack of stiffness in the legs is not weakness of legs, it usually is weakness of core & glutes. If you just concentrate on the cramped muscular area, it might come back time & again. There should be a detailed assessment of your weakened muscles & an appropriate exercise program should be followed to prevent it in future. Fascial manipulation done by certified Physical therapists along with Taping works well to fix this temporarily. Since you asked for an oil, you can try Mahanarayana Tailam which is available in many medical shops.