Hi left sided pain abdomen can be due to gastritis , left sided colitis or rarely due to left
kidney / uretric stone.
As per your history this looks like you are suffering from colitis. A ultrasound of abdomen is required to rule out same.
You can take probiotics like ECONORM SACHET daily for 5 days.
Next Steps
A physical examination is mandatory in your case. consult a good surgical Gastroenterologist.