Is not reporting the same IP that I see at whatismyIPaddress.com

And Ipconfig in my Command line isn't reporting the right one either.

On sites that do IP checks, I'm certain the one I'm seeing is the one I'm assigned by my modem.

I don't know why my OS is reporting a different one. Like it's being masked or something.

So how do I "unmask" it? XD I will need the correct IP for personal use.

Edit: Did a bit of searching and it seems comcast put me on a private network.

It's normal for the modem to have a different address on its "public" side to what you're seeing on your computer: it would typically assign an address in the form 10.x.x.x or 192.168.x.x for your internal network (even if it's just for your PC to talk to your modem). This isn't a problem, the modem will worry about doing the routing, translation and other faffing about required for you to connect to whatever you need to connect to.

What is your control panel?

What kinds of addresses are being reported by: ipconfig, your control panel, and a public server? If you don't want to state your full addresses, just the first two octets are sufficient (ie: 123.123.x.x)

I personally use: http://icanhazip.com/ and http://www.whatismyip.com/ (the first one being perfect for simple things and getting via the command line since it's plaintext, the second one will try to detect proxies which is useful at times).

All that said, as vometia mentioned, it's perfectly normal to be assigned a private IP address by your router and have a different public one. However, I can't see why you'd have three IP addresses unless you're using something like a VPN or connected to multiple networks at the same time. I'm reading your OP as you saying you have 3 IP addresses (one being reported by your "control panel", one by ipconfig, and one by public servers)

As others have mentioned, it's normal (and IMO desirable) for your PC to have a different IP address than your modem. In most cases you want your modem to connect to the internet and then have your local devices on a subnet so that outside forces can't access your local devices directly. This helps to protect your local devices from nasties like worms. As DEFRON mentioned, though, I'm not sure why you'd have 3 different ones. Do you have multiple network adapters, or possibly a wifi adapter in addition to an ethernet adapter?