Sounds like it wasn't done correctly to me. If you were trying to save any data on the device when you reset it, that can lead to problems if the phone had something on it that it shouldn't have. Virus, malware, etc. In that case a full wipe "Hard Reset" would have been needed. I am including the correct instructions for this type of reset below (just in case what you actually used was something else). If that is the case, then try it using these instructions. However, if they are the same as what you did, then you may have a more serious problem and should have a tech look at the device.
NOTE: Doing this will clear 'all' the data on your phone, so it is suggested you not choose this option unless you have to, or aren't worried about...