A peptic ulcer is probably the cause of your dull ache.
A peptic ulcer can mean either an ulcer inside the stomach or in the duodenum - the upper part of the small intestine. It can be result of a diet rich in fatty, spicy food, stress, ciggarette smoking or alcohol. To know more about peptic ulcer, please see:
Another cause for a dull ache in the left side could be a stone in the kidney. A stone can be the focus of a mild infection that comes and goes, causing the ache.
You need to consult your doctor and ask for tests like gastroesophagoscopy, gastroscopy, Ba-swallow xray (an Xray taken after you drink a substance called barium), and a special Xray called Intravenous Pyelogram (IVP) to check if you have any stone in your kidneys or anywhere in the urinary tract.
I hope this helps.
Let me know if you need more input. If not, please click on the green"Accept" button on this page. Adding a bonus and a positive feedback will be warmly appreciated.
The other symptoms of peptic ulcer could be indigestion, acid regurgitation, abdominal bloating, pain that increases on an empty stomach or just after eating, nausea, pain that can radiate to the back or anywhere in the abdomen etc. You can read more about this here:
Kidney stones can cause a crampy pain or a dull ache on either side of the abdomen, depending on whether the right or the left kidney is affected, the pain may be present at the back, just below the ribs. You may have burning or frequency of urine (f you have an infection), and the pain may increase while passing urine if the stone gets dislodged. You can read more about this here:
I hope this helps.
Please feel free to ask for more information if you want any. If not, please accept the answer by clicking on the green 'Accept' button on this page. Leaving a bonus and positive feedback would be much appreciated.