I have a hatred for clen for scaring me like that, so i normally stick to ephedrine for my fat burning purposes. I have had a few of those what you talking about. Very shap pains in the chest area. When i was doin 120mg-200mg clen it happened. Ripped, yes, worth it , no. If you cant hang with the stims, your best bet is to drop them and maybe consider thyroid or an ephedra alkaliod product like sida cardofilia. Those tend to be much more mellow. The "y" is completely unnecessary and shouldnt be taken with that stack. Im no pro, nor do i want to be, so my health is a major concern and i hope it is for the rest of you guys too. Chest pains, not trying to go there.