ok well, everyone else has adequately covered all but point #4 about your foreskin... You're saying you can only pull it back (retract) when you're not erect? this isn't totally uncommon, it can just mean you have a tight foreskin, not everyone's is the same. whether it's a problem or not depends on if it's painful at all, or is interfering with your ability to have sexual pleasure. Depending on how tight it is, there are a few options, one is treating it with hydrocortisone cream, and over a period of time trying *gently* to work it back over your head and perhaps you can stretch it, OR in the very worst case if it is causing you a lot of pain, the docor may have to make a tiny little snip in the underside of the foreskin to allow it to move freely. do NOT and i repeat do NOT allow anyone to tell you that you need to be circumcised from a tight foreskin. In almost ALL cases, it can be treated with minor methods. But unfortunately depending where you live, some old-fashioned doctors are very quick to suggest circumcision. In case you're wondering, I know all this because my foreskin also has a really hard time moving back when i'm fully erect!
Hope this helps!