What Causes Stabbing Sensation Around The Sternum And Flatulence?

Question : I have this stabbing/prickling sensation around the sternum - more towards left side of chest. It is very short in duration - 3-4 seconds and occurs once or twice per day for the past 4 days.
I've also had a lot digestion issues over the past 1-2 months. A lot of burping/Flutulance and I am on a very strict diet (no sugar/ breads/ dairy) just protein and vegatables. I thought with this diet the symptoms would disappear.


My Health Profile -

- Excellent Physical Condition - run 4miles per day 6 1/2 minutes per mile.
- Feel Pretty Good in general with the strict diet. Protein and Vegetables. No sugar, breads, dairy.
- Not a Smoker / Drinker.
- Bad Chewing habits - eat very fast without fully chewing the food. Trying to do better.
- Height 5'6". Weight 140.

Ran today for 4 miles without symptoms (no chest pain / nausea / dizziness, etcc...) symptom free.

All blood work up tests are within normal ranges except the following:

Issues:
1. B12 - low. Started taking b complex supplements. Originally level was 290 mg. Do not understand why. I am not a vegetarian. Which leads me to believe some type of mal absorption issue? After taking B12 complex, level went up to 452 and began feeling better

2. Kidney Function - a bit compromised. Depending on when you take the test. Creatinine level has been measured - on occasion - at 1.5. Normally (most of the time) it is 1.2-1.3. Very tiny kidney stones. No pain.

3. Cholesterol - High HDL = 95 LDL = 150, Triglycerides = 45

5. Heart - had a "million" tests. Other then the "Gold Standard". Everything negative. Passed the treadmill with way above normal results - athlete level. Echocardiogram, Calcium, etc... all negative. Do have a family history of heart issues.