why my truck is running sideways

Go to alignment shop,front alignment problem,center bolt in rear springs,brake pulling,tire O.O.R. Alignment shop should be able to find your trouble.

Check tire pressure. If its not tire pressure it may be misalignment of the front and back tires. Tire balancing can also be a factor in swerving while driving. Another possibility can be road conditions. And with extremely worn shocks/struts this can also happen.