Tummy went rock hard, felt like I had a tennis ball in there..

[Traveller]

It sounds like braxton hicks. The round lump could have been because of the way your baby is lying in the womb. It won't hurt to speak to your OB or a midwife but in the absence of bleeding or pain then it sounds like normal BH's.

[~Kim~]

I was going to suggest the same. My BH have been like that.

[NaeNae]

I'd say it was either BH or bub, Bub more so if the rest of the area was soft, BH if it was your entire area nothing to worry about x

[AMumma]

I have spots that go hard on my tummy its the babies head, bum or back pressing against me. I normally give it a poke and baby moves away.