Regular brief headaches, same spot, throughout the day

For the past 3 weeks I've been getting very brief - 10 to 30 sec - headaches in the same spot throughout the day. Left side, just above and slightly behind my temple. They seem to happen when I've stood up. Like getting off the couch to go pee - and by the time I'm standing at the toilet, the headache hits. Yesterday I had been standing at the kitchen counter and walked away to go to another room and by the time I got there, the headache hit. This has been happening up to about 6 - 8 times a day. There have been some times when I'm not moving at all and the headache will hit, last 10 seconds, then fade. I mentioned it to my Primary a couple of weeks ago and he gave me Meloxocam to take every morning. That didn't help at all so I stopped. These are not debilitating in strength... uncomfortable nevertheless. Nothing has changed in my life to account for this start-up. I'm 74 and in generally good heath. I take a blood pressure med and my pressure is good and stable. Thanks for any suggestion.