In my experience of over 81 years, I've found life responds well to healthier habits -- in foods and drinks, variety of physical activities that strengthens and increases range of motion, and of course a sound sleep (with a 30 min nap), and not the least a few friends with whom one can have a meaningful connection (This last one, I'm trying full-time to develop.)

So how good I feel? I do have moments of pain when carrying heavy groceries thru steps, can do many floors up and down in my bldg and tried to see other day how many push-ups and at the seventh I was teetering!.
But the good thing is our bodies seem to get better to reach optimal level for OURselves. That means I don't have to compare myself with others, just for myself a fairly fit body is a vehicle for pleasure and work I want to do with my life.
Hope you find your balance...50s seems too early for your symptoms.