For Last Couple Of Weeks I Have Had Difficulty Breathing.

For last couple of weeks I have had difficulty breathing. Just going up stairs from basement or doing a simple easy task makes me low on breath. Especially bothersome when lying down - must take deep breaths. On a side is better than on the back. Essentially cannot sleep... Also just bending over to tie my shoe laces causes breath loss. I have a clogged hear artery & will be going for bypass surgery. Am Type 2 diabetic. What is wrong? What do I need to do?