Yes I can sympathise with you on that I'm newly dx and am on sinemet x3 a day,
keeping to a regular timing with meds but one day good next awfull , it can even change morning of afternoon n that really is annoying, I also seem to have a persistent head ache that I can't shift.
I have found that the more active I stay the better things are in general though n have been doing stretching exercises n squats to keep my joints moving ,I hold on to the sink n squat down and up again ,best to have someone near by in case you can't get up though lol.
i get lots of knee n leg pain / stiffness and find this helps though check with your dr or pysio first.
I hope things settle down for you soon take care.
Live well. Cc