Day 3 My strong " broken" back

So I am having a serious TMS Episode but I got lax took my improvement last November and ran with it doing nothing to eradicate the TMS happy with just a reduction in pain. So I am here till it is gone completely. One good this is on the question on physical activity , compared to the last time I did the program my response is night and day. Lat time I spoke of hiking and wanting to go out for longer and hoping to go to the gym one day. Now I am weight lifting !!! thats right I had a L4-L5 double fracture and I have 6 pedicular permanent screws holding my back together and I am dead lifting 70kg and squating 95kg . I had not lifted a coal scuttle for over 20 plus years now I am lifting my doberman 45kg and boxes the same as any normal person with no back pain from any of it. Yet If I sit for long my lower back and neck kick in as normal - my mind going through the pattern matching of " well dose'nt our back die from sitting?? yes ? Great well lets crank up the pain ....about now" So How can I lift massive weights with no problem yet sitting is excruciating ? TMS It is one sneaky clever cookie. But I am on to it .