Thank you for your query. I would like you to clarify a few points. 1) how long has she had the pain for? is it getting progressively worse? 2) where along her back is it? and does the pain radiate( travel) to any other point? 3) does she have any dimples or out of place patchy areas on her back? 4) any numbness associated with pain?( leg feels heavy or like pins and needles) 5) any rashes along the painful areas? 6) you mentioned one point which makes it worse( sitting in her booster seat), how about other worsening factors and what makes it better? 7) has she had any injury to the back ( slides, swings etc)? 8) who have you consulted? pediatrician , neurologists? 9) does she feel pain when she tries to touch her toes without bending her knees Based on her symptoms, I would like to rule out Spina Bifida occulta ( a mild form of the neural tube defect which goes mostly unnoticed and asymptomatic). narrowing of space between the vertebrae or bony spur formation that puts pressure on the adjacent nerves need to be ruled out as well. Answers to the above questions will help to understand the situation better . I recommend seeing a team that includes the specialities of pediatric neurology, neurosurgeon, spinal surgeon, pediatrics. hope your little one feels better. please get back to us if you need any clarification . wish you both good health