If I pray normally and shake or quiver while bowing or in another pillar of the prayer but wait, let us say 2-3 seconds, is my prayer okay? I ask because it is difficult to stop all movement in the pillars of the prayer. And what if someone would swing during the whole pillar of the prayer whilst standing?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Slight shaking or a quiver or stillness during the prayer do not affect its validity. The same applies to swinging during the pillar; it does not affect the validity of prayer because it falls under the category of insignificant movement that is pardoned in prayer. You must avoid Waswaas (obsessive doubts) and not get carried away with it; verily, getting carried away with it leads to a grave evil.

Allah knows best.