Talk to Neuro Physician on B.P Fluctuation And Pain In Left Side Of Head Slightly Above The Ear

I am feeling Blood Pressure fluctuations from the last one month. Mostly Blood Pressure remain low from the last one month. I reduced my weight three time from 2015 till 2022. first time reduced from 96 to 80 in 2015. Second time I reduced the weight from 95 to 72 in 2018 and third time in 2020 I reduced from 87 to 75. My current weight is 93 KG. These days I feel pain in left arm from elbow to the fingers. Today my Blood Pressure was 120/40. Could not sleep well from the last three days.. Last night 6 hours sleep, yesterday 3 hours and the day before yesterday it was 6 years maximum. I have attached the picture where I am feeling pain in head especially when the BP is low. I would request the Doctors to please suggest me which doctor should I visit? Today I went to the Chughtai Lab and given my samples for different tests like Cholesterol, CP, Lipid Profile, RFT, LFT etc... Should I go to the specialist of Brain also to check for Brain diseases like Brain Heimoorage? I need detail