Why knee was swollen and pain around knee cap when waking

Nine weeks after TKR I woke up with swelling and irritation (some pain) around the knee cap. This is the first time experiencing much pain around the knee cap. During the day the discomfort continued and I used ice therapy to help with the inflammation and pain. I am not sure why this happened and would appreciate any insight or suggestions.
During the previous day these are some things I did that may have contributed to the issue:
During my PT workout I did an exercise with an exercise band for the first time to strengthen the hamstring. I also knelt on a soft cushion for 8 minutes, this was the first time knelling on a cushion for that long.
I wore a compression sleeve on my knee for 6 hours of the day.
I massage the scare and around the knee cap to try to help break up scare tissue. Maybe I was too aggressive. I do have more movement of the knee cap today.
During the night I woke up a couple of times with my leg in a awkward position that put pressure on the knee.
Please let me know if you have any input, Thank you