Now, I know doctors don’t care for us using the 'net to try to diagnose ourselves, but I’m positive I’ve pinpointed something that’s starting to bug me.
My blood pressure has always tested low at the doctor’s office, which was nice, because I don’t have to worry about high blood pressure and its attendant problems. But in the last couple of years, I note that having a glass of wine at lunch results in my heart and veins feeling throbby and a general faint feeling. Even a slightly larger than usual lunch, sans wine, can bring on the same sensations. I started Googling today on the term “low blood pressure”, and voila, I see that for people with LBP, alcohol, ibuprofen or a good meal can bring about these symptoms. Other factors, such as antidepressant drugs, can trigger symptoms.
Additionally, I think I figured out another long-term pesky problem: I occasionally get a fluttery, trembly sensation and sound in one ear. It’s not a ringing sound and it’s not a pressure-cracking sound. Again, I Googled, and discovered that it’s Leudett’s tinnitus, a kind of nervous tic of a tiny little muscle deep inside the mandibular/inner ear area. Nothing harmful, just annoying – but it’s gratifying to finally figure out what the hell it is.
Ain’t the internet grand? Has anyone figured out an obscure affliction through the 'net?
Hey - you can cure that! Just get a salt lick 
We’ve diagnosed Dweezil’s encopresis that way. Just stumbled across a description while searching for something else, and went AHA!!!
Also my Restless Legs Syndrome.
Standard warning: if you find something that lights up a lightbulb in your head and explains everything, it’s a very good idea to have a medical professional confirm the self-diagnosis. After all, IANAD and the folks who wrote the websites probably aren’t either 
I had to ban myself from surfing WebMD. When my hair starting falling out from stress, I decided (via the internet) that I had lupus.
The stupid thing is that real health problems I often choose to ignore. After a few years of experiencing occasional heart arrythmia, dizziness, and surface blood clots, I decided to visit the cardiologist. Bingo! All caused by low blood pressure. Regular meals and exercise alleviate many of the symptoms.
Sage advice, Mama Zappa, about not depending on a self-diagnosis. What with my crappy insurance, though, I can’t see my doctor for more than about 45 seconds at a time, so I am grateful to be able to learn about minor stuff. Anything major, I’m off to the M.D.
And yes, I try not to just surf medical sites, or I’ll imagine all sorts of horrors for myself. I try to be specific about symptoms and cross-check several sites against each other.
Oh, I forgot - also discovered I have irritable bowel syndrome the same way. Metamucil is now my best friend.