Back Labor ??

Je

So I’m a FTM currently 39 w 4 d and I had the worst sleep ever last night due to intense lower back pain that keeps coming and going since about 1 a.m EST till now almost 9 a.m EST it’s only been in my back (nothing in my pelvis) so I haven’t started timing them, should I start now or wait until they move to the front ?

Side note: My husband and I did have sex last night.