[n00b on demand]

So yesterday when i was driving around with my windows down i heard this rattling noise that I usually only hear when im traveling uphill and the rpms's are over 2k. Started up the car this morning only to hear the same rattling....tried to isolate where it was coming from and its right underneath the passenger seat...or at least very close to that area. So I'm thinking the main culprit for this noise is the heat shield . When I was changing my oil last time i knocked around to see if anything was loose but it didnt seem so....my guess is that it would only seem that way when the car is running but im definitley not doing that with the car on. I know that they are bolted on there but with all the salt and winters its probably rusted on there although i can see some of the bolts. I dont have any tools to get them cut off either. I guess my only choise is to take it to the exhaust shop?