6 speed shifter prob

i went to back up into a parking spot yesterday and the truck would not go into rev so i let clutch out 3 or 4 times and tried to get it to go in like iv always been told to do when eventually i had to kind of force it in because people were waiting on me and after i got into the parking spot when you pull the shifter over toward the 1st and 2nd gear side it does not pop back up to the neutral position between 3rd and 4th if any one has any idea what might have caused this or any questions because i realizr it is kind of hard to put in to words... any help would be much appreciated