Problem 1: I am using a 50 caliber TC round ball along with a TC titch patch pre-soaked in boar butter (.018 thickness). The last time I shot it, it took some effort but I was able to start the ball and load/shoot. This time, I couldn't force that ball into the barrel with the patch to save my life and I am a big strong dude. The ball was actually deforming instead of loading. My workaround was to load and shoot without the patch. The ball would sometimes stop at the barrel and take a very small tap to load and sometimes would fall in all on it's own. [question: why would it load last time and not this time, nothing has changed--I am using the same equipment. Perhaps use a thinner patch or do I even need one?]
That is strange. The few things I can think of that might cause it are
1) As someone mentioned, it could be that you didn't clean and lube it right last time.
2) As someone else mentioned, you may have assorted size balls in the same box. Could be poor quality control from the factory. Could be a couple boxes got spilled and mixed up at the store. Could be one of your buddies messin' with ya snuck some oversized balls in there.
3) You might have had 2 patches stuck together.
Since you shot the rifle with no patches you now will need to clean the lead fouling out of the rifling. The patch is there to form a gas seal and engage the rifling. It also keeps the lead from fouling the bore. Your rifle can be fired with no patch but it will work much better with a proper fitting patch/ball combination.
If you have a micrometer or caliper measure your balls and find out what size(s) you really do have. I'd probably get a box of .490 balls and try them with .018 and .015 patches for a start.
Problem 2: I switched to a TC hot shot nipple system that uses musket caps (presumably to achieve more consistent ignition). Today, I only got three shots out of the gun before it started refusing to fire--again it didn't happen last time like this. I tried several caps in a row to see if I could burn it out. Finally I had to remove the nipple system, clean it out the best I could, and then prime the pan a little to get it to shoot.
I'd switch back to the #11 caps because they will work fine, they are easier to find, and they are cheaper.
You have gotten some good advice here already but there are a couple of things I would add.
1) Your T/C has a "patent breech" where there is a smaller diameter chamber at the bottom of the bore. You MUST get that chamber clean and dry when cleaning the gun. Then you must get any oil out of that chamber before you shoot the gun again. Also be sure to remove the nipple and clean out the flame channel with a pipe cleaner. And don't forget to clean the nipple itself.
My guess is that you oiled the bore good and then stood it barrel-up in your gun cabinet so some oil settled in the breech and fouled it.
2) A percussion gun doesn't have a "pan". I assume you mean you put a little powder under the nipple???
At the range I run a slightly damp spit-patch or 2 followed by a dry patch only when it starts to get hard to load easily.