Do you have back pain or problems? If you have had to change your life, eg. avoid doing something, or stay home due to your back or if it hurts often that's "having back problems"
If you are taller than 164cm (5' 4.5") you are "tall." (In this formulation more men are tall than women, I'm interested in absolute height here so not breaking it down by gender. Data are bimodal but I don't think it matters much.)