these are just my personal experience and opinion and should not be taken as advice, just as an additional minor perspective.
firstly, it is very difficult to determine whether a symptom is pd, medication or something else, especially in the elderly. cutting off meds would prove it but thank god that is a practice that most doctors have stopped.
painful neck - probably the easiest to put down to pd. check her posture when reading, watching tv or on computer etc head tends to jut forward like a chickens (just like mine right now!)
bloat - very very common. but pd or meds? its either water, poo or gas. for water need to see doctor. for poo check for constipation - increase fibre (soluble (fruit) and insoluble (bran)) - for gas ? is it worse after dairy or wheat or coffee? is there burping?
palpitations - my palpitations are associated with bloating. in my case, reducing the bloating reduces the palps. not necessarily true for anyone else, but i know of a few similar people, particularly AF (atrial frib.)
urinary frequency - problems with pee are common in pd but there are heaps of other potential causes.
burning feet - fortunately not one i've had but for a few pd people this sort of pain occurs. part of pd. not sure what can be done for it. is there toe curling?
if anyone's experience differs, please help by adding comments.