and pain are suggestive of Gastrointestinal tract problem.
Hiatal hernia may cause upper abdominal pain
.But,diarrhoea is not seen with this condition.
is a type of Inflammatory bowel disease
that can affect any part from Mouth to Anus.It may lead to all the three complaints that you have mentioned.It runs in families too.
Please consult your Gastroenterologist and get investigated.
Regarding moderate abdominal pain on left side,it may be due to left Renal/Ureteric stone.Simple test like Ultrasound
abdomen will exclude the stones.
If Ultrasound abdomen is advised by your doctor,then any other lesion causing the pain can also be found out.
Wish you good health