iPhone 6plus won't backup

My iPhone 6plus is acting strange. I cannot answer texts and it keeps partially shutting down. I get the "apple" screen, but then when I TRY to shut it down, it won't give me the "power off" screen. More importantly, it won't allow me to back it up. I get an error that says: "iTunes could not back up "my iPhone" because of an error. The community has suggested corrupt photos, so I imported all of them (it let me do that) and a message told me 2 (of over 1,100 files) were not importable. I deleted all the photos off of my phone, but I am still getting the same response when trying to backup and same issues when using it. Since I can't reboot it all the way, I am wondering if this may be the problem at this point. Any ideas?