Devil Sent the Rain — D.J. Butler

In this urban fantasy, rock and roll musicians with supernatural powers gets trapped in an alternate universe -- inside one of their band member's minds.
 
A trap set for the band goes from bad to worse as organist and resident sorcerer Adrian badly bungles his escape spell. Trapped inside Adrian's shadow, the band struggles to orient themselves and escape not only from their pursuing enemies, but from the darker manifestations of Adrian's soul.
 
And once they do get out from inside their own wizard's tortured mind, they'll still have to deal with the fallen angels that trapped them in the first place.