Hey there, dj dallas11.
Please also ensure that you install the DDJ-SR driver, which can be found that the page that Tecniq has linked above.
Open the SETUP menu > Mixer, and check if 'Master Cue' is on - this may affect your headphone volume.
Please check that your computer meets the minimum system requirements at our product page:
serato.com
If you can, please test your DDJ-SR on another computer which meets these requirements as well, and see if the same issue occurs.
Let me know how you get on.