Flush vs. Flush

[Norm]

What are the odds of having suited cards at the same time another opponent also has a suited hand in the same suit?

If you flop a draw with a medium suited connector, what is your exposure to the higher same suit flush draw?

[speedracer]

Happened to me last Friday. I held K, J of hearts, and flop came 10, Q, 4 of hearts. Made flush and 4 to royal on the flop.
Another player had A, 9 of hearts. Not fun...