Stabbing pains are a concerning symptom, especially in the chest and abdomen. I would recommend that you see your primary care doctor
regarding this. I understand that you have done so already, but specifically addressing a few of the below concerns are worthwhile.
Chest pain is concerning because it can represent problem with the heart. In a young, otherwise healthy person, this would be rare. That being said, if you are obese or have a family history of heart disease I would recommend having you heart evaluated. Another troublesome cause is a pulmonary embolus (or blood clot in the lung). This can cause pain in the chest.
Another common cause is gallstones. These often cause right sided pain on the high abdomen and low chest. Often it is worse after eating (especially a fatty meal). An ultrasound
of the liver and gallbladder can assess this.
Inflammation in the lining of the lungs or heart can cause this. Rheumatologic disease such as lupus can cause this. Blood tests for lupus and similar disease may be helpful. Inflammation in the muscles can also cause this. This is often a diagnosis of exclusion.
More rare causes could include kidney stones
, stomach ulcers or pancreas problems. See your primary care doctor. I would start with an ultrasound of your gallbladder. Good luck!