For a few months post surgery I was just very tired and took naps every day. The pain subsided within 2 months and Tylenol was a big help. When I took walks I had to take lots of breaks and would get very winded. I would tell people I felt like I was walking through molasses. This summer I started swimming in our lake which was very beneficial. I did wear a swim belt while I swam. My physical therapist recommended the back stroke which helps to strengthen and stretch the chest area. Recovering from the trauma of the surgery is huge, But, my symptoms were very different than before the surgery when I had lots of dizziness, head aches, loss of stamina, hard to breathe, etc. Now 6 months out I feel great which I feel you will too with time.
It is also a process to figure out the medication routine which has been altered a few times to my benefit. I also do breathing exercises regularly which really helps to control blood pressure and help the lungs to stay strong. I also got an Apple Watch to monitor my heart. My surgeon recommended it. I can take EKG's to monitor for AFib and keep track of my heart beat especially while doing exercise.
Good luck. I am happy to share more. You will be fine.