Hey buddy, I'm a locksmith for the last 9ish years and have replaced many many ford ignitions. They use a sidebar type ignition and either the key or the wafers wear and create issues with the sidebar not retracting correctly. Best solution is buy an OEM ford switch (Autozone/AdvanceAuto ignitions are garbage) and take it to locksmith to key the same as your existing key. He can probably cut you new keys by code also at the same time so the key works perfectly. There is a chip in the head of the key, we sell them for $16 a piece.
This is a really easy problem to fix, as long as the key still turns the ignition. If you get to the point where the key won't turn you're looking at lots more money and aggravation. Where are you located?