I've been building my house for several years and the master bath has never been finished. The shower head and dual handle knobs were installed a while ago but the shower has not been regularly used. I just completed installing the sink fixtures and drain. The sink has low water pressure and the shower just trickles. When the shower was first installed the pressure was okay but now it's practically non-existant. All of the fixtures are new and the whole house has a water softener so sediment and/or mineral build up shouldn't be a problem. Any thoughts?

First remove the aerator of the sink faucet and check for debris.
If there are no valves in the water lines to the bathroom that could be closed, remove shower valve stems and flush the valve.
What kind of pipe and who did the plumbing? If copper pipe and plumber used too much solder, the solder can run inside the joint and then break loose and block valves.

Are the shut-offs on the supply lines turned back on enough?
When we moved into our house, we had to turn up the water pressure to the master bath.

Hi Tabitha...

You didn't turn up the "pressure" to the master bath... not something you guys can control.

More likely here, is that you opened the shutoffs and increased the "volume" of water available to the faucets... ;)

Very common for people to confuse the two... Just so others are clear in the future!

Mark