Re: Anal itch and itch on tip of penis
The first question that has to be asked is if you engaged in any anal sex recently. You do not have to answer this question on this site, but it is something to be considered. Note, even if you used protection, this could still possibly be a reason.
If the answer is no, then you may have two separate issues. Anal itch can be caused by hemorrhoids. There are topical items available in any pharmacy that can be used. This may seem obvious, but also keep that area as "clean" as possible. This may include washing after each bowel movement (if possible). Additionally, slight dietary changes may help, such as adding more fiber. Even a younger person can get have hemorrhoids, but it can be managed easily.
As for the itch on your penis, if it is not related to any STD, it could be as simple as your clothing (rubbing?) or detergent (allergic response) or, again, cleanliness (of you or your clothing).