1998 Isuzu Trooper Odd oil pump issue

I have an odd reoccurring oil pump problem. When I start the car on most mornings I can hear the distinct ticking of low oil pressure. If I turn the car off and restart it goes a way. Some times it may come back in a mile or so. Again if I turn off and restart it goes away. This time for the rest of the day until it cools down, then the cycle starts over again. If I do not restart and keep driving the ticking will get very strong and not go away immediately, but all of a sudden it will stop but it takes a much longer time than restarting. What could be causing this?

Thank you!