Had mi 4 months ago and stenting now aching all over?

See your doctor. Get checked. It could be your medicine (statins namely) or signs of new blockages. Get checked asap.
Possible Side-effect. Many patients who have a coronary stent have an elevated cholesterol level and this is usually treated with a 'statin' medication. These statins can cause muscle achiness in some patients. Rarely, this medication can even cause serious muscle damage. I would urge you to see your doctor and mention your symptoms to see if this might a a side effect of your medications.