Hi,
thank you for providing the brief history of you.
I will advice to undergo a thorough musculoskeletal clinical assessment.
Post which you can be guided further. Usually, with clinical assessment, the ortho comes close to the diagnosis and if he feels there is a need of
MRI to see the
soft tissue status with in the knee joint he will recommend one. Based on that you will be advised simple medication and
physical therapy.
As, you are 56 year old, there may be a possibility of soft tissue damage in the knee joint where it is swollen and painful as well. Also, due to ageing of tissues and wear & tear of the soft tissues, the mechanical changes occurs in the soft tissue which can allow it to get injure and give symptoms of pain and swelling at any time.
Getting assessed by an ortho will be of input to your health and functional status. Post this physical therapy will help to regain the strength in the muscle and avoid any future injuries by which your activities of daily living is fulfilled.
In my clinical experience - the combination of rest, medication and physical therapy provides 99% of regaining mobility in patients. I am sure you will also be fine soon.
Regards
Jay Indravadan Patel