For flexibility/mobility yoga really is where it is at. I wouldn’t write it off so quickly because you think it’s boring. Even 15-20 mins a couple of times a week could be really beneficial. You don’t have to do long sessions or go to classes (although that’s helpful in the beginning for form, etc.). I do 30 min videos around three times a week (I use the Gaia streaming app but Amazon has some good ones too), nothing hard or fancy, but it has done wonders for fixing the imbalances from years of running high mileage. I just wish I had got into this habit sooner. I’ve never felt better and the improved hip mobility is really helping running.
I’ve got similar problems also and just about the same age …
My solution (and I know everyone’s solution will not be the same …) has been regular yoga and decreasing my stress level (my back tenses up then everything else follows …)
I know you’ve mentioned that you’re not interested in yoga … I had felt the same way. Thought it was all airy fairy stuff and only women in fancy tights did it but this isn’t the case at all. A good quarter to third of the yoga classes I’m in are full of athletic men … trying to improve their strength and flexibility. Some types of yoga can be incredibly challenging … balancing on one leg or your hands, planking, core work … all of which gets my heart rate up. Have a look into flow / vinyasa or hot yoga classes which have been the magic pill for me. I don’t have the discipline to DIY yoga and stretching so I go to the classes.
My piriformus also likes to whinge a lot so I roll them every night. That and my glutes getting knotted up have caused very awful back pain. My routine now is while I watch tv, I sit on my roller and off I go …
Speaking at a 60+ athlete with lots of racing behind me the years between 40 - 50 were easy. I think that as we age that a good all season strength and flexibility program is required. I regularly see my chiropractor and massage therapist, typically every 3 - 4 weeks year round with visits every two weeks in peak season. I need to manage my sleep (target average 8 hours minimum each night). Nutrition and hydration become more important as well. I try to train pretty consistently all year round with only a few peak periods for IM builds. I find that if I can keep in good shape most of the time peaking for big events is possible/easier. As pervious posters have suggested if you have lots of residual pain from workouts in joints you should consult your medical professional.