Hello and welcome, Thank you for your query. At first let us talk about any patient diagnosed with hypertension. All such patients can have fluctuations in blood pressure despite being on regular medication to control the same. This could be as a result of changes in lifestyle, stress, diet, lack of exercise, etc. Such fluctuations are normal, although they should be brought to the notice of the treating physician, so he/she can monitor them and accordingly advise. Next, the general population experiences symptoms similar to the description you have mentioned above. This could be caused due to the following reasons: -Indigestion or a developing stomach infection -Gas trouble (in simple terms) -There could be palpitations (which can be caused due to an increase in BP, due to any of the above mentioned symptoms, or even others) -There could also be a heart ailment, which might require a thorough check-up Although your father might rule it out as something minor, it is best to take him to a doctor to ensure proper care and management, and to rule out the worst for a long and healthy life. I hope I have succeeded in answering your questions, you could write back to us anytime for further clarifications. Best wishes.