Ever since I've been pregnant my tailbones been sore never had an injury?

Relaxing substances. During pregnancy your body releases relaxing substances to help loose he birth canal. The coccyx - ie tailbone can have increased movement and could have been strained. Sometimes this heals on it own.On occasion we have to inject it like we would inject a knee, shoudler, etc.
Common preg problem. Tailbone and hip bone pain are really common during pregnancy and tailbone pain is even more common after vaginal delivery. It has to do with the anatomical changes that occur during pregnancy. Tylenol (acetaminophen) is a good choice for medications. Heating pads, stetching, yoga and massage are allso good options.