I switched out my shower head with an Oxygenics and immediately noticed a huge improvement in water pressure. I got mine from Menards, but you can find them on Amazon or at any home improvement store.
I’d first check for any build-up or gunk in the shower head. Pull it and see how the water flows without it. Could also be a flow restrictor. Pry it out if possible. And I second the vote for an Oxygenics shower head. They work wonders. I use them at home, too.