Before self-medicating your self-diagnosis, see an orthopedic (knee) specialist. Osteoarthritis is a common cause of knee joint pain in seniors, which will feel like it is muscular. Another cause could actually be in the hips and not the knees. All it takes is an x-ray. I would recommend seeing
Optimotion Orthopaedics. They have an office conveniently located on Rt 44E near Brownwood. If osteoarthritis is your problem, then there are various treatments available.
I had both knees replaced in 2022 after probably 5 years of pain and some loss of motion. Zero pain since then. Yes, I tried chondroitin, etc. first. Results vary depending on fitness and rehab. I returned to full athletic activity 6 weeks after each replacement. Age 70. Fit. Played two hours of pickleball each day for four months before the first replacement.