Right Out Of The Blue, I Have A Sharp Pain

Right out of the blue, I have a sharp pain in the lower left side which seems to be below the stomach area. It started yesterday and continued through the night. This morning it seemed to get a bit better; I had taken an arthritis strength tylenol. Now it has started again. It feels sort of like a pulled muscle or sprain. I have been weeding a couple of flower beds which may have some bearing on it.