Nothing is ever a silly question. The only silly/stupid question is the one that is never asked!!!! Welcome to HW anything.... while it is NOT true that cracking your knuckles can cause arthritis it can contribute to it. Does that make sense? Cracking them in itself will not cause the disease. The "cracking" sound that you hear when you crack your knuckles is the ligament popping/sliding. Don't know how else to describe it. With repetative cracking you can weaken/stretch/harm the ligament which can lead to damage to the ligaments around the joints. As with any repetative motion, over time damage can occur. It doesn't always happen. I cracked my knuckles for years and still do but that did not cause my arthritis however because the joints have been weakened over time when my arthritis flared up (due to psoriasis) the weakened joints were a prime area to be affected.
If your joints feel tight and then feel better after you crack them then I would be looking at a ligament issue. Do you use your hands alot? ie. are you a computer person who spends hours aday typing? What leads to the "tightening"? Can you nail down a specific time that you start to feel the joints becoming stiff? If you are having a lot of pain than I would get into see your Dr and see if you could be develping arthritis or if it is more of a tendonitis. I'm sure that Erin and the others will be along shortly to welcome you and add (or correct, if needed) to what I have said.
God will never give us more then we can handle, I just wish that God didn't trust me so much.
Remember healing comes one step at a time, sometimes it seems that its two steps forward and one step back, but ultimately, always in a forward direction!!!