Decided to go out biking again, but my pedals won’t move forward. They work fine backwards and as well as when the rear wheel is lifted. They also work when I remove the front chainrings. But whenever the chains rings are on or when the rear wheel is on the ground the pedals immediately become stuck.

Welcome Noxious!. You obviously need some Harder Hittin' Breaker/Cracker pedals

I need at least 10 posts to URLs. My imgur account is Nxious8 so you can look at the videos.

Go to a bike shop and ask where people can see it?

Im pretty sure it’s a freewheel and yes the back wheel can be spun forward. I think it might be a bottom bracket spindle problem.

Someone told me that the freewheel ratchet could be stuck under the load and as well as the bottom bracket. They say it can be fixed by lubing the freewheel. What do you think?

Shift to a lower gear?

I think you might be on to something there... haha

If the freewheel pawls are stuck, the wheel will still be able to move forward. Stuck pawls just turn the freewheel into a fixed gear.

Or a no gear bike. We see more freewheels with their pawls not engaging then we do of freewheels that are "locked up". Andy

I've followed this thread with some interest. From what is really meant by "my pedals won’t move forward" to what the problem turns out to have been. Like so many threads here I suspect the problem is relatively easy to find with the basic deductive process, easiest done with the bike in hand.

I watched your video and it certainly looks like a freewheel problem to me. Maybe others can actually watch the video and make a suggestion. I also think if the bike is that old a full overhaul of the bottom bracket wouldn't hurt at all.

https://imgur.com/gallery/0TYwzgI

Your first video shows the drivetrain working normally, but the second shows the "lockup". Were these videos taken at different times?

I don't see a freewheel problem in your second video. You are able to put tension on the chain and the freewheel has locked to the hub through its pawls. It appears that the wheel itself is preventing proper operation.
Are your brakes on? Is the axle mounted so that the tire is centered between the stays (and not rubbing). This looks ok in the video but we can only see one side. I also don't see much of a bottom bracket issue - if you can spin the crank backwards it can clearly spin forwards.

Check your brakes and how your wheel is mounted.

If the bike is parked, the pedals aren't going to rotate forward, unless you lift the rear wheel as in the first video.

Or are you saying they won't move forward even if you are riding the bike?

-- NVM: Is this a troll??

If I saw you standing on one pedal and it wouldn't move, it would have more impact.