My first year of med school, a professor said something like this: "they say that doctors make the worst patients, but in my experience, they're the best. They come in, sit down politely, and immediately describe their problem in the proscribed order of 'Chief Complaint - History of the Present Illness - Past Medical History' (roughly the order they teach med students to interview patients) and they don't waste my or their time with extraneous information."
While I was in med school I had see a couple of doctors about issues and I tried to keep everything as simple as possible. Don't volunteer random information, answer the question directly in as few words as possible, etc.
Our medical system (at least in the US) is ridiculously over-stressed. Doctors are busy, tired, overworked, etc. The more you can adequately explain yourself in short, direct, declarative sentences, the better. Instead of bitching about how much your side hurts, you tell the doc, "it's a constant dull pain about three-outta-ten and it spikes to eight-outta-ten whenever I exert myself," it makes it easier for the doc to make her notes, process the information, and deal with it.
In my first ever clinical prep class (called "The Art of Medicine" or something similarly pretentious), I remember the lecturer asking us something like, "How long do you think the average family physician lets the patient talk before interrupting?" and students were saying things like "five minutes" or "two minutes" or something. The lecturer then laughed and said "under nine seconds."
I remember thinking, "well no shit! People are fucking morons (including me!!) so of course you have to interrupt them to get to the relevant information!" Little 21-year old me at my very first clinical exposure busted out laughing when I opened the patient's chart and saw the med student before me had written out this longass description of why the patient's finger was hurt, like he was just taking dictation about a sports injury when it all just boiled down to "jammed finger." You think the doctor is going to read six fucking paragraphs describing the injury when it's just a jammed finger that needs ice and maybe, maybe an X-ray?
I've not actually needed a doctor myself in the two decades since med school, but if I did, I certainly wouldn't try to talk over their expertise and interject my own knowledge. Keep it short, keep it simple, and ask questions in as few words as possible.
(Yeah, yeah, INB4 "ironic that old man spews a thousand words saying to use few words.")