Mcm mne rse contraction palsu?

Eh, those sound like Braxton Hicks contractions la, basically your uterus practising, so the tightening comes and goes without a regular pattern, unlike real labour contractions which get stronger and closer together. The lower back pain on one side plus the on-and-off belly hardness could be normal, but since you're also having abdominal pain, better check with your doctor or midwife to make sure everything's okay, a few of us had similar symptoms at different stages and some were nothing, but some needed checking out, so better safe than sorry!