I realize this is 7 years after the original post, but I thought it might be helpful to reply for those suffering the same symptoms who may just now be reading this.
One of the common symptoms of PD is involuntary muscle contractions and spasms. Aside from being painful, this, along with poor posture and unbalanced repetitive movements and positioning can cause musculoskeletal misalignments that pull your body away from its natural center of balance. This is often one of the main causes of the balance problems that people with PD have while walking.
If you can afford it, getting weekly Deep Tissue Massage can be very helpful in softening the muscles, releasing the contractions, calming over-excited nerves and easing or even eliminating the pain. Stretching is also very helpful. It doesn't have to be a yoga class, as you can find stretching tutorials online. Also try being mindful of your posture, being careful not to slouch, noticing when you're leaning or shifting your weight one way and consciously leaning or shifting your weight the other way.
As a massage therapist and personal trainer, I currently have 3 PD patients that are greatly helped by these natural therapies. I'm not advertising my services - just sharing my experience in the hopes that it helps someone.
Ultimately, "HealthCare" is you taking Care of your own Health. Going to the Doctor and taking medications is "SickCare." The more HealthCare you do, the less SickCare you need.