39 weeks pregnant and for the past few days my belly is tight and hard all day. is it normal for it to be hard all day?when i lay down it relax a little but stand back up it's hard again. been having pressure in butt and pain in lower stomach

Braxton Hicks: You sound like you are experiencing Braxton-Hicks contractions, sometimes called "practice contractions". Your uterus is contracting, which is why it feels hard. Generally, this is not concerning unless you are experiencing painful contractions - that is a sign of labor. However if they are painless, it is not likely labor. Pressure is also normal. You should have your doctor check your cervix.