For back pain in your third month, Acetaminophen (Tylenol) is the safest oral pain reliever to use. You must avoid NSAIDs like ibuprofen, naproxen, or aspirin, as they can carry risks during pregnancy. For topical relief, applying warm or cold compresses is highly recommended and completely safe. While mild menthol-based ointments can be used sparingly, avoid any creams containing salicylic acid or prescription anti-inflammatories. Non-pharmacological measures like gentle stretching, prenatal yoga, and wearing supportive footwear can also offer great relief. Always consult your OB/GYN before starting any new medication or ointment.