Back pain/ back ache

Hi mummies! I’ve really bad back ache/pain, idk how to describe. It’s been too frequent. Managed to req to wfh today. But I still feel it’s been very tiring for me to go to the office everyday. In addition, the chair there really doesn’t make me feel comfortable and make it worse. Sometimes I’m at the point of giving up work because I’ve got to go everyday now. But I really can’t afford to stop working. Helps any advice? Also is this normal as im only in my 18 weeks. It’s only half of the journey 😣