Daughter was diagnosed with strep 2 days ago, on liquid antibiotics since. is some neck pain normal at this point? (she says back of neck).

Maybe,maybe not: You didn't mention age. It is not uncommon for the glands of the neck to become swollen during any throat infection & cause neck pain. This is more frontal than back but general aches & pains are common to strep.If the DX was confirmed by test & the child is improving otherwise you may be ok to wait. If she appears no better & the neck is stiff i would call in & see if a recheck is advised.