sounds like it is most likely pvc's. some people feel them in their throat so why not between their ribs. you will know soon from the holter but in the meantime try cutting out carbs at your meals - i mean simple carbs like bread, pasta, rice, sugar... because for a lot of people who get them after meals it is because they have eaten carbs that cause their insulin levels to rise to rapidly and for some reason this seems to affect pvc's. it definitely does for me and since i have cut them out for the most part except for the occasional splurge i have minimal pvc's. i have also been taking 500 mg's of magnesium which i am sure has made a huge difference as i have not had to take my beta blocker once since starting the magnesium. both suggestions are risk free - give them a try. good luck and keep us posted on your holter results