I had an ultrasound today and there is a hole by my right kidney not allowing a good blood flow, what is it?

It's unclear: Your description isn't great - by no fault of your own as you aren't a medical professional - but it sounds like a cyst. It's a bit unusual that it's so large so as to be compression either the renal artery or vein but not impossible. Though again, this is a guess. It could be something else, but there aren't many "hole"-like structures that appear by the kidney. Hope this helps.