I've been playing for 30 years and if I start playing more than I usually do, or start practicing a song that has more bends that what I normally play, my fingers will get sore. My finger tips will get tender and the muscles in my fingers will feel fatigued. It will go away quickly, in a day or so.

It would help to know what style of guitar you play (blues, metal, etc.) and what type of guitar (electric vs. acoustic).

It could be as simple as you need to add some variety to your practice routine. Just like a gym routine will one day be heavy on cardio and another heavy on strength training, you want varying emphasis on your practice routine. It could also be as simple as changing the guage of strings you use on your guitar.

Is the discomfort to the point where is is painful and bothers you in a significant way away from the guitar? If so, it may be a cause for concern and you should cut back or change your routine.