Liquid Dip Tube Stuck

I'm on my second keg and I'm learning some of the lessons that many others have posted about - racking too much hop sludge (pellet) from the primary into the keg. I picked up a stainless steel cover for the end of the dip tube, but I've run into a problem... I can't get the dip tube out to put it on!

From everything I've read here and seen on YouTube, the dip tube should pull out easily. Not the case with this keg, sadly. I've tried pulling it out by hand and even attempted to grab the tube a little more securely with pliers, but at the risk of shredding the o-ring I gave up. So I took off the lid and tried to push it up from the inside, but again, no luck. Didn't even budge.

Any suggestions for getting the dip tube out? Or should I just rip up the o-ring using pliers?

No, don't use pliers. You will damage it. It's probably stuck from old dried soda crud. Soak it upside down in very hot water first. Then grab the dip tube from inside the keg and wiggle it until it's free and it should pull out. The other possibility is the dip tube is slightly bent and resting on the bottom of the keg preventing it from being pulled out. Make sure the dip tube is free at the bottom and can move around when you wiggle it.