Motherboard audio jack problem

[Xyst-Patterns]

i just built my first PC last December so i'm still getting new things for my setup. i've had a pair of Astro A40's for about a month and decided i wanted some speakers for gaming without my headset or listening to music. eventually i bought the Harman Kardon Soundsticks iii and when they arrived i was eager to plug them in and listen to music. After i had unplugged my headset from the Audio out and Mic in jacks i took the single 3.5mm jack from the speakers and plugged it into the Audio out port. i was immediately greeted with a really, really loud screeching noise to which i unplugged the speakers very fast and then plugged my headphones back in. after that i used the speakers by plugging them into the headphone port on the back of my monitor. the first time i went to use my headphones again (which were plugged into the audio jacks from my motherboards IO) i started up CS:GO and went to search for a competitive match. Before joining the match i noticed i couldn't hear certain sounds such as the clicking sound when i navigate the in game menus. i reset all the sound settings and it still didn't work. i decided to try the audio somewhere else to see if it was messed up there too so i went to YouTube and searched for Trap Queen and listened to it. the problem here was i couldn't hear any words at all and some other sounds didn't come through. i thought my headphones were at fault but then i decided to try and plug my speakers into the audio out jack and they were missing all the same sounds from the song and CS:GO. i have also been through all my sounds settings and reset to defaults. So now  i don't know what to do and i think my motherboards audio is messed up. Can anyone help me?

Also i'm sorry for such a long story.

[Samppa221]

Have you tried the front ports?

[Xyst-Patterns]

i'm trying them as i type and they're working fine. sorry i was at work.

[Xyst-Patterns]

can anyone else help me with this?