Hello @freedancer69,
I am not sure if you read my little open heart surgery story here or not? I addressed the gnarly sternum, the unexpected back pain and not being able to lay on my side for several months.
This is all part of the process and every person will have a different response and healing time.
Give yourself time to heal, you just got home!
Every day will be a little better. It just takes time. It's not going to heal overnight.
You will not be able to start cardiac rehab for awhile. It's too soon. Some doctors want you in right away, some have you wait at least six weeks. Rehab gets your arms moving, walking on the treadmill, all sorts of light exercise while being monitored by the staff.
My sternal wound took about three weeks to start looking better. I was not happy how it looked, but it is a battle scar to remind you that you went to battle and won!
Walk as much as you can. Drink water and eat healthy for healing. Sleep when you are tired. Don't lift heavy things. Try and do a little more each day. I was encouraged to shower every day, and even that was tiring at first.
I was not on O2, so I can't share anything, but your medical team would be the one to ask that question...we are all different.
Here is my story:
https://connect.mayoclinic.org/discussion/what-i-learned-from-my-open-heart-surgery-part-1/