so 2 days ago i was doing a deadlift and i felt a twinge i took it easy doing the rest of my back workout, i was fine till 3-4 hours later i was sitting at my pc for a few hours and i could barely get up, let alone walking, struggled to lie down.

the piriformis muscle was tight and that is where i felt ALL the pain that was stopping me, seems like it was so tight it was pressing into my sciatic nerve causing me the pain, 

after sleep i kinda recovered but losing slight bending as i could feel it

day 2 after sleep i have all manouverability back but if i stretch my ass back any way i can feel the twinge.

i may have to take time off my workouts but what could of caused this and what steches should i be doing to avoid this in the future

Sounds like your hips are rising before your back and quads take the full load of the bar. These types of stresses deep in the Glutes occur when the butt rises quicker than the back and legs when deadlifting. The body should move all in on fluid motion - knees to glutes to lower back such that no one muscle group is taking the majority of the load on the bar.

If your issue is due to tight hamstrings, then hamstring stretching exercises are in order. Pinching of the sciatica with adequate lower back flexibility is usually a sign of tight hamstrings which keep the pelvis from pivoting upwards and places extra downward flex on the pelvis. This in turn puts downward pressure on the lumbar spine and the foramen for the sciatic nerves.

John

Awesome advice from John.

I'd suggest a mix of hamstring and glute stretches. For the hamstrings you can do things like put your heel up on an elevated platform so you have a straight leg to stretch the hamstrings.

For the glutes, you can lie down on your back, and then bring your knee up to your chest/face to stretch the glutes.

Also try foam rolling your entire posterior chain if it's tight.