I am installing a walk in shower and I would like to relocate the drain and shower head to the opposite wall. Should I raise the floor to relocate the drain or cut into the slab.

Since you have the floor open, I presume, I would cut the slab. Easier to put a raised floor in, but far less appealing. Is the shower going to have a curb? I have seen people run plumbing through them.

The PTRAP is under the floor and you need to drop straight into the PTRAP so you can't run the pipe above the floor unless you remove the old trap and that means opening up the slab, SO, do the job right and break up the slab and relocate the PTRAP to the side you want and drop down straight into it from the shower pan!

Mark