Hi when i take a deep breathe i feel a sharp pain in my lower left back, it comes and goes, i was in the garden sweeping and collecting leaves etc

Muscular pain likely: 26 y/o female. If you have been raking/sweeping leaves recently as a new or much increased level of activity, then most likely you have some muscle strain and your diaphragm is a muscle that attaches into the back also and may give you intermittent pain until it heals some. Gentle stretching of your lower back in all directions to the point of hurting and holding it there briefly will help it.