Hi, welcome to iPF!
The symptoms you're describing can be caused by debris or an object in the headset jack. Look at it, and if you find something there, try to remove it, if possible, but be careful when doing so. If you can't do it yourself, visit the next Apple Store.
If there is light debris, such as lint, in the headset jack, try connecting the headphones to the headset jack and then remove them. Do this several times to remove the debris.
What else you could try:
Make sure your device isn't muted.
Reset your iPad: press and hold Home and Power button simultaneously until the Apple logo appears, then release both and let the iPad power up on it's own.