I’ve heard that the Lightning Network will require my bitcoins to be locked up…Is this correct?
“Locked up” is a very misleading term in this case.
Lightning will not make your money less accessible.
The fact is that your money will actually become more accessible when held in a Lightning channel.
First of all, you do not need to wait for confirmations in a Lightning Network. Your money can be moved almost instantly within this network.
Second; bringing your money “back on chain” is just as easy as sending a normal bitcoin transaction. You just wait for the first confirmation and your money is no longer “off chain”
One exception is the rare case that your channel breaks down in the middle of a transaction (counterparty goes offline)
In this exceptional case; you will be subjected to a short delay before you can spend your money. The length of this delay will vary; depending upon the parameters you have applied to your channel (the range is estimated from a few hours minimum, up to a couple of days maximum)