Is it legal for a friend to talk to me who is being investigated for illegally touching a minor?

Yes, it is legal. In addition, MCL 767.5a provides; "Any communications between attorneys and their clients, between members of the clergy and the members of their respective churches, and between physicians and their patients are hereby declared to be privileged and confidential when those communications were necessary to enable the attorneys, members of the clergy, or physicians to serve as such attorney, member of the clergy or physician. However, if the church member is speaking to you as a friend or in any capacity that falls outside your duties as pastor your conversation is not privileged and you may be compelled to testify about it.