I Am 54years Old Women, Obese, Take Venlafexine 250mg Cut

I am 54years old women, obese, take venlafexine 250mg cut to depression and two type of blood pressure medication , last few days I have got only right leg paining , all over specially sheen or calf mussels , I work as a support worker , full time , quiet hard work , but I don't do any exercise , now pain is too much that driving is painful. As breaking or accelerometer use is terrible pain ? Only one leg ?
Could you please tell me why? I do smoke a lot .