transmition prob (AT)

92 Accord LX 2.2L

my automatic transmition sometimes seems to get stuck in 2nd gear, and won't shift. From stop it takes off slow and then even when I get to 50, 60mph or faster it will not shift. This is an on and off problem. I can go for weeks with no prob. the get a bad day of on and off. Any ideas of whats wrong? is this an expensive problem?

I really appreciate any feedback! Thanks.