Principles of sports medicine
1) If doing something hurts, stop doing it. Doing it more won't make it go away.
2)Stop thinking you're still 25 unless you're still 25.
3) The only real way to know if you need to see a doctor is to see a doctor, unfortunately
4) Ignore medical advice from any site that wants to sell you something.
5) If your doctor tells you you have condition X and then walks out the door before you can ask questions Wikipedia is an excellent source of information as is Pubmed (the national library of medicine site).
Principles of sports medicine
Acetaminophen can do severe damage to your liver if too much is taken. That may be the source of the idea you heard it's worse for people who drink. If they already have compromised livers, it may be easier for the Tylenol to cause harm