well, muscle fatigue and some pain from lactic acid (from needed to stretch, etc.) are normal... Sharp pains may be lactic acid. If that's the case, you should stop for about 10 minutes, and stretch out your arms, legs, and torso.
However, you could be experiencing a number of other things, including carpal tunnel syndrom, tennis elbow, or any number of other problems caused by tendons, etc., that flare up. This is usually heriditary, and you can't do anything for it. I have bad tendonitus, carpal tunnel, and should problems, and it causes me to hurt a lot, and even not be able to play some days.
If this is the case, you can wear a wrist brace/elbow brace, and you can also ice your joints down. Heat doesn't help any. Also, IB Profeun (sp?) helps, b/c it is an anti-inflammatory drug.
Other than that, the only thing you can do it practice for shorter amounts of time, but have more intervals. So, like 30 min, 10 min break, 30, 10, 30, 10, etc. You can also change your kit setup so your arms don't have to do as much reaching, etc.
Finally, you may have improper technique. For the most part, if your technique is proper, you shouldn't be hurting. Again, having some of the above imparments make you hurt, regardless, but they aren't very common (lucky me...). Try analyzing your technique, maybe get some books about technique, etc., and make sure you are drumming properly. That can help a ton. That's worked for a few students I've taken on that came to me with pains during drumming.