Do you keep a daily note of your pain level? @johnbishop recommends keeping a log of daily pain levels from 1 to 10, and I have found that useful. It could show you whether the activities you do are the likely cause or if a reduction has prompted it. If the pain is not getting worse, it may not be a flare.

With my flare last year, the pain level increased very gradually over a number of weeks, starting when I reduced to 6.5mg and increasing further after I reduced to 6mg, at which time pain was 5-6/10. A blood test confirmed inflammation had risen. Do you have regular blood tests to check your inflammation levels?

Have you tried splitting your dose and taking a small amount of the daily dose with dinner? That has kept many of us painfree in the mornings. I occasionally have aches and stiffness (not even 1/10) in the morning after overdoing activity or following a reduction, but it always passes.

You're doing well to be keeping so active. As you say, it helps bones and is recommended for anyone with PMR - as much as we're able without overdoing it.