My fasting blood sugar checked daily is in 140s but my after meal and random numbers are all normal. My last a1c was 6.4. why high fasting?

Need for glucose. tolerance test. Repeat fasting glucose of 140 is considered diagnostic of diabetes. A1c is not a sensitive marker for diabetes. If you have doubts, you may get a glucose tolerance test, however, it would be prudent to alter your diet and life style in keeping a diagnosis of diabetes mellitus. Exercising and losing about 10% of body weight may stabilize the disease. Consult this site for info:
Need to see your doc. Your GP can help you sort this out. I suspect that you have pre-diabetes or early/beginnings of diabetes. Your doctor can confirm it an guide you regarding your diet and exercise needs depending on your weight. Weight reduction can often normalise blood sugar in the early cases like yours.