I don't know your specific circumstances so I'm just going to say a bunch of random stuff that might be relevant.

There are a million good reasons to not want to be touched by anyone, and even if you can't pinpoint a reason, that doesn't make your reason (or your feeling) non-valid.

If people in your life want to touch you and this creates issues when they find out you don't want to be touched, the issue is with the relationship, with how both of you set and respect boundaries, and possibly with them. The issue is not with you.

If this is something you want to change about yourself, for whatever reason, then pushing yourself, being mad at yourself, or rushing yourself is not going to help. If you don't want this right now it's likely that you're not going to want this for a long while.