This Pali dictionary says:
vipariṇāma : [m.] change.
aññathā : [adv.] otherwise; in a different way.
Sutta Central says:
vipariṇāma : change (for the worse), reverse, vicissitude
aññathā : in a different manner; otherwise (than, ablative); in the wrong way, falsely
Both words mean change or change for the worse?
Can it be that during existence aññathā is just change (which is annoying)? E.g. I watch out of the window and see cars and people passing by. Although I can watch it for a while it will become annoying after some time. This change causes dukkha and can be subtle. That is how Waharaka Thero explained it. This “otherness” or change is burdensome (pilana). Therefore the pancakkandha are burdensome or to experience the world is dukkha.
Then the question is, what category is physical pain? Such pain is a change for the worse, it can lead to “destruction” or vaya of the person. Thus it can be viparinama dukkha. If not destructive it is aññathā or dukkhadukkha.