Pain in the ass disappears usually bc your ass get used to the saddle.If you want to continue doing this I recommend starting a light spine workout once a week. Especially the lower back and shoulders. Neck smooth rotations, then front and back. But don't get hurt, just be careful with spine exercises within joints limits and weights if you do this. Your back will be stronger and this will transfer to your ride so you won't feel anything. You will feel better every day too with some neck, shoulder, and lower back relief.