Adult with mild CP - Tizanidine vs. Baclofen?

I have right-side mild spasticity caused by cerebral palsy (CP) that occurred as a baby with a massive stroke. Growing up most focus was on my leg with just some OT to help get some basic dexterity in the right hand. Now 51, my right upper body is the problem with it locking up with tone, starting in my shoulder blade and then spreading to the rest of my right upper body. My PC doctor gave me Tizanidine instead of what I usually see prescribed which is Baclofen. Anyone have thoughts on why one vs the other?