Also check the attaching nut/bolt that attaches the lever to the end of the shift column under the dash.
One other possibility is that you have a broken shift tube in your column. If so, replacing it takes about one hour and wrecking yards have good ones for about $50 each. You don't need to remove the column - All that is needed is for the column to be dropped enough to access the broken tube which is on top of the column. No point in replacing the whole column, though that is what most will tell you.
When mine broke a few months ago, I took my van to a local wrecking yard and waited while they replaced the broken tube - One hour and $115 later.
