I applied for a 4th credit card from a retail store and was denied but was told on the spot i have too many open..what does that mean?

You have too many active credit cards compared to your income.

If you had higher income - you would qualify for more cards.

But - if you are using the cards you have wisely - you don't need more cards.  If the balances on your current cards are maxed out, that will also hurt your chances for getting another card.

The easiest way to have more credit cards is when you don't need them. 

It means that you were denied because you applied for a 4th card. They keep track of that stuff. You have applied enough; now you need to stop.

It means you have too many open.  Stop wasting your time and theirs.

Stop applying for credit cards for a while.

It means STOP APPLYING FOR CREDIT FOR 2 YEARS.