Hi @briianthebee, 
Welcome to the Parkinson’s UK forum. 
Sadly, coughing and saliva issues are not uncommon for people with Parkinson’s and there have been discussions on the forum about it, one of which you can find here: Coughing & excess saliva - #2 by gus
Many people with Parkinson’s develop problems controlling their saliva, which can lead to drooling or dribbling. The medical term for this is sialorrhea. When you have Parkinson’s, the natural tendency to swallow slows down. We all swallow many times a day, but the slowing down of movement that people with Parkinson’s experience may reduce this. If you swallow less, saliva can pool in your mouth and, instead of you swallowing it, it can overflow from the corners of your mouth. We have more information and tips on how to manage this via our website here: Eating, swallowing and managing saliva | Parkinson's UK
In some cases, improving your posture or the way you sit can help. Physiotherapy or occupational therapy may be beneficial. For example, an occupational therapist may be able to recommend a tilting chair that will help your head and neck stay upright.
Ultimately, I think you should speak to your GP or Parkinson’s nurse about the issues you’ve been experiencing so they can refer you to the therapists mentioned above or they may need to review your medication. We also have a free and confidential helpline with a team of advisers that would be happy to provide you with more support on this. Give us a call on 0808 800 0303 or email us at [email protected].
I hope you find this information helpful.
Best wishes,
Reah
Community Manager