Ovulation pain + backache 3DPO?

Hello! Probably reading too much into this but I'm having a dull achey ovulation pain/twinge feeling, Feels similar to ov pain around ov time but this is duller rather than mildly crampy twinges.  I'm 3DPO confirmed by +opk and temp rise (got my peak 8pm on day 16 and suspect ovulated early AM day 18).  Anyone else experience this and if so what does it mean? Implantation doesn't take place until 6-12 DPO right?  Thanks!