To be honest, I don't really know enough (yet) about how wrong positioning on a bike can contribute to something like bursitis - if it was a one off (hopefully) then prob due to impact of the knee or infection as I said, but if it happens again, it would perhaps suggest something in your bike setup may need adjusting. I always recommend anyone with bursitis of the knee to go along to the doctor just in case the bursae are infected, as it may need antiobiotics, and/or a good doctor can actually drain some of the fluid out of the sac. Otherwise, just apply the principles of RICE - Rest, Ice, Compression and Elevation, to the knee, and something like Ibuprofen as previously suggested to ease the inflammation (tho that is just a masking effect of course, you'd still need to take it easy), until the symptoms ease - which is effectively what you did. Glad all seems well now!
