Baby tenses up

Rachel
I know I ask a lot of questions but I'm a ftm and I would rather have advice from y'all rather than google. 
I'm 37weeks pregnant and every time im lying still the baby seems to tense up. Then I get this hard bulge on my right side. Is this a sign of going into labor? I haven't seen my mucus plug yet and I was 2cm dilated at 35weeks.