tylenol while pregnant

Hi lady! As of today I am 4 weeks pregnant and the back pains are killing me. Still trying to keep it secret until my husband gets home later this month so I can't carry around a heating pad without looking suspicious :p My question is, is it ok to take tylenol at this stage in pregnancy or should I stick it out? A lady at work is pregnant and can take it but is 4 months ahead of me. Any other suggestions to manage the pain? 😬