My car was running perfectly fine until I pulled over to make a phone call. I put the vehicle in park, and when I went to shift back into drive, the shifter was free flowing and would not go into gear. I'm thinking it might be a linkage problem.
The linkage for the gear selector is located inside the steering column. Over time, continuous usage of any mechanical part will cause wear and tear, and eventually failed components. An inspection of your transmission should be carried out by a qualified technician to find out exactly which components have failed.