The best replacement for pains is contractions.

The best alternatives to pains are rated as following:
★★★★★  contractions
★★★★  braxton hicks
★★★★  heart attack
★★★  pangs
★★  labor pains
★★  pain
★  hunger pangs
★  gas pains
★  ectopic pregnancy
★  bone cancer
★  constipation
★  family ties
  trapped wind
  miscarriage pains
  menstrual cramps
  shin splints
  osteosarcoma
  chest pains

Your alternative for pains is not listed? Suggest!
Speaking about pains, one probably shouldn't forget about gains.

Other search terms related to pains and their ratings are:
★★★★★ gains
★★ water breaking
You have in mind a companion for pains and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of pains in all years. Click on graph for more.
pains
contractions
braxton hicks