I've been tweaking my fit for a long time with success as the bike gets more comfortable for me with the changes. Not every change is a success so it is helpful to have a way to get back to a previous position. I use a white dot from a whiteout pen to, for example, mark the seat post position. A complication is that your body will change as you get stronger so that a previous position may no longer be optimum. In any case, the advice to relax is good. By relaxing as much as possible you may be able to detect where muscular tension is present that that may be a clue the root cause of discomfort.