2014 engine noise and performance

I have a 2014 make noise as others have posted on start up, whether cold or hot... Sometimes when cold but not hot and sometimes when hot but not cold but usually makes the noise ( sounds like lifters clattering ) also have a solid sounding thud drivers side wheel well and most recently seems the exhaust is muffled. Truck doesn't have the throaty rumble it had when I first bought it. Low RPM power seems somewhat sluggish and if throttle is applied slower at normal speeds seems kinda sluggish and stumbles some what and slow to downshift. Anyone having / had any similar issues???

any recent mods such as tune?

All factory, except drop K & N air filter.