I started to have lower and upper left abdomen pain yesterday. The pain is constant and gets worse when lightly touched or when I move. Causes?

Need exam. Depending upon where you are in your cycle and if it came on all of a sudden, you may have a cyst on your ovary or a ruptured cyst. There are also some more unusual things. An exam would be helpful.
Can't tell here. Could be lots of things, ranging from musculoskeletal problems, constipation, to serious internal issues, including but not limited to: ulcer (with or without complication), gyn issues, kidney stone or infection, bowel issues, infections, etc. See your doc.