Ive broke three ribs on three seperate occasions riding my bmx.
I found that i couldnt do much of anything for about 3-4days then after that it was a bit painfull to ride for about another 2 weeks but it was bareable for ME, and from the second week till about 2 months later it only hurt when i fell off, sneezed, coffed, tool a deep breath which im sure your feeling now.
do not strap your ribbs up at all because it causes your lungs not to work properly and you will catch pneumonia, well thats what the doctors told me.
If you have had it x-rayed then just check how it has broken because if its broken inward then there is a chance it could puncture your lung so be carefull.
I still cannot take a breath as deep as i could before i broke them and i havent broken any ribbs for atleast 10months now :P
So to sum up ride if it doesn't hurt too much and check your not going to punture a lung :)