38+4 weeks really sore... please answer...?

hey im 38w4d pregnant, last week my docter told me baby is only halfway engaged sucky for me, anyway all yesterday ive had an acheing lower back just above my bum crack haha and last night i had a hot bath to help but after the bath it was worse to the point that i was in tears, ive been having braxton hicks on and off and they arnt regular so i dont think im in labour, but al last night and this morning and right now the ache in my lower back has gotton worse, im so sore, i have to walk really slow or it hurts more and ive had a panadol ive had hot baths but nothing seems to be helping... also when i do pelvis rocking it feels like my lower back is clicking..strange, this is my first baby so i wouldnt know whats normal but honestly are they aches meant to hurt this much, and has anyone experienced this please let me know and what was causing it...