I'm a native speaker of English but I've been pronouncing Hepatitis as He-pa-tit-is all my life. I was told that this is wrong. How should it be pronounced then and is the way I've been saying it okay/normal too?
No, there is no "tit" sound in 'hepatitis'.
Questions like this are very difficult to answer because we don't know how you pronounce 'He-pa-tit-is'.
I would approximate it by "Heppa Tightis"
The primary stress is on 'hep' with a secondary stress on "tight".
IPA /‘hepə,taɪtəs/
How do they want you to say it?
HEP-ah-TYT-us