Can you soften rock hard almond paste? It will be mixed in a food processor if I can soften it?

Something I would try for a hardened ingredient like this (or brown sugar or dried fruit, etc.) is to mimic a steam oven with your microwave. Place a clean wet cloth or paper towel in the microwave and heat it up until it is steaming. Then place the item you want to soften into the microwave with the cloth, and warm it on a lower power setting at short intervals until it is the softness you want. Should work - our steam oven works well for "refreshing" things like this so I think it's worth a try.

You could use a grater or a microplane. It won't make it softer, but it will give you smaller bits to incorporate into your recipe.

Have you tried short bursts, ~20 seconds, in the microwave?

If you don't have a microwave, try wrapping in foil and putting into a warm (~200F oven)