iPhone 5s seems to take F-O-R-E-V-E-R to sync with iTunes

My iPhone 5s not only does not show up in the device list unless connected by the lighting cable (unplugging it always makes it disappear from the list), when it is connected by the cord, it takes at least 30 minutes or longer to sync (with iTunes 11.1.5). It seems to hang at the very beginning and also Step 4: transferring purchases. It didn't use to take nearly as long.

Anyone experience this? Any remedies?

Thanks.