Deep water aquafit and toe pain

Hi all, I just have a quick question. I've been doing deep water aquafit 2-3 times a week for the past couple of months and I've noticed that my fingers and toes can be quite achy the next day. Any thoughts on what causes this and how to prevent it?

I have been diagnosed with costochondritis, which is a chronic inflammatory condition in the ribcage. I'm starting to wonder if there's a similar inflammatory issue going on in my small joints.

As a side note: I'm 33.

Thanks!