My shower is on and so is the tub what should I do.

Where is the diverter located -- Is it a lift lever on the tub spout, is it a push/pull button on the escutcheon or is it a knob or lever on the volume control?

Is this a recent development for a valve that has worked fine in the past -- Or is this a newly installed valve?

Knowing the brand and model # of the tub/shower valve would also be helpful.