How do I manage abdominal aching in pregnancy?

Abd pain. In most cases, rest will help or stopping the activity that triggered it. Tylenol (acetaminophen) can be used safely. If no relief from that, changing positions may help. If still no relief, call your ob.
Support. Discuss your aching with your doctor as it can be a symptom of preterm labor or other complication. If deemed to be a "discomfort of pregnancy", a belly band can support the uterus and help with discomfort.