Dear Helen,
well, it all depends on whether you feel that the exercises are helping and not causing too much increase in pain. Some increase in pain may occur, but so long as you don't bring on a flare-up then I don't see a problem with carrying on. In fact I think it is very good to keep as active as possible to prevent deconditioning which leads onto lots of muscle aches and pains whenever you try to do anything.
So do keep at it if you think it is worthwhile. Let us know how you get on
Regards,
DocSarah