Dubious. I play classical bass for 4-8 hours every day and weights hit your hands (and forearms) a lot harder. I would look towards a technical problem in your fingering technique - you could be putting too much strain on a joint by positioning your arm improperly - are your shoulders relaxed or do they tighten up? What type of guitar do you play? Classical guitarists always seem to have to address posture on a consistent basis, and tend to put in more practice time - its a double whammy, then. Alexander technique is helpful for some, while other people need to just retrain bad motor patterns… The Art of Practicing by Madeline Brusser is a good book to look into for any musician. If you actually believe you are straining your hand so much stopping the strings on the frets - I would be concerned about your instrument’s action, the tension of your strings, and inefficiency of your technique. But, it does sound on first read that you are probably putting your hand in an unnatural position for a prolonged period of time and the stress of this posture is weakening something.