I have a terrible backache today.

我今天背好痛。

Poor posture can cause backache.

坐姿不好会导致背痛。

She woke up with a splitting backache.

她醒来时腰痛得厉害。

I'm going to the doctor because I've had backache for a week.

我因为腰痛一周了，所以去看医生。

Taking a warm bath can help relieve backache.

洗个热水澡可以缓解腰痛。

希望这些造句对你有所帮助!