I have arthritis, osetoporosis & a curvature to lower back, should I stop working as a cleaner?

Not necesssarily. These chronic conditions need to be treated. They may not go away by you changing your occupation.
No. Exercise is beneficial for most types of arthritis, osteoporosis, and scoliosis (curvature of the spine). Physical work needs to be customized to the individual based on the severity of their condition. Work/exercise should not be done in the presence of acute inflammation.