Welcome to HCM,
You have coronary artery
disease and treated with angioplasty
and stent in LAD, I presume you must be taking other medicines which are given to you,
Your description of pain may be anginal so it is better to take rest and take sub lingual nitrate and see if it is relived or not which will help to differentiate and if not then visit to ER or cardiologist and get a ECG to check that every thing is normal or not,if there is any suspicion then anti anginal therapy may be increased and then it may be investigated to see ischemia
and stress thallium later on.
If it is not ischemic then it could be muscular pain
or even acid peptic disorder both can be easily treated.
Please take care