When I stop the car, sometimes it will not move forward from 1st gear but if I reverse it will clear the issue. Then I'm able to drive forward in 1st gear again. Reverse seems to reset the car. What can cause theses symptoms?
What is the exact behavior when the car will not move forward in first gear?
If it feels like the car won't go into gear (i.e. the shift lever doesn't drop into position in 1st gear), this is likely an issue of a worn shift linkage or problems with the transmission dogs. In either case, "walking through" reverse can help.
Sometimes, a transmission will come to rest in a configuration that doesn't allow a gear to be selected because the dogs don't line up with the holes into which they are supposed to fit. In order to then select this gear, you must move the transmission somehow. This can be done by selecting a different gear and rolling the vehicle a bit, then trying again for the gear that you previously could not select. You can also sometimes simply keep pressure on the shift lever towards the gear you are trying to select, while slowly releasing the clutch. As the transmission input shaft starts to turn, the transmission will "pop" into gear.