The stain on your ceiling is rarely under the hole. Water enters at the flashing, runs along the roof deck or down the outside of the flue, and surfaces wherever gravity and framing let it. That is why the first job is diagnosis, not sealant — sealing the wrong seam is money spent to keep the leak.
Dallas has a telling seasonal pattern: leaks that appear weeks after a hail event, not during it. The storm lifts or dents the metal without producing water inside, the homeowner concludes the roof came through fine, and the actual leak arrives with an ordinary rain a month later. If you have had hail, the flashing is worth looking at whether or not anything came through the ceiling. And if the crown is part of the problem, crown repair gets quoted alongside so both entry points close in one visit.