What can make sugar level rise though eating well & walking and taking the medication as prescribed by dr. some days its in range while some days high?

Probably normal: Blood sugar responds to a large variety of internal and external cues. Sometimes up and down due to factors beyond control. General goals are to keep fasting blood glucose around 110 mg/dl and 2 hour after meal numbers below 140. This corresponds to a hemoglobin A1C of about 7.0. Don't care too much about the short term numbers if the A1C looks good.