i checked my oil and i found out that i was running with 1/3-1/2 qt extra oil... (drove for like 1000 miles.. seems ok)
i drained it a lil bit and i turned on engine to warm up...
came back and i hear the sound underneath the car maybe from the header cat exhaust connection...
i dont know any thougnts?

 

When the cat gets hot it can makes strange creaky-screaching noises. I have noticed them when turning the car off. Metalic expansion/contraction creaks, sometimes very loud.

I suggest you recheck your oil level again and more frequently in the future. In a thousand miles you would be expected by the factory to have checked it 4 or 5 times.