What Causes Burning Sensation On Calf Muscles?

54 yrs male with severe burning sensation in the lateral aspect of calf muscles in siting position. it relieves on lying since 2 months . CABG done before 4years. Nerve conduction study of both lower limbs in norma. he is diabetic since 10 years. it is under control. (110 mg/dl random).he is under Envas 5, mg, Metalog XR, Clopitab A75, Atorva 10, Glimet DS.