The 6+2 pin does not go into the motherboard - that is a PCIe connector. Keep in mind, you should not need to force any connectors. The reason it was hard to fit is the connectors don't fully match. You want to use the 4+4 connector from the non-modular part for that connection - the two halves match up together and then fit into the motherboard
Sir, now i feell like an idiot but thanks for the help it was what you said, THANKS!