Hi.. Lifting heavy weights can cause harm your back.. The harm can be in the form of a prolapse of the disc or can be secondary to the back muscle strains.. You need to be on rest and avoid exertions especially on the back for this to improve.. The other treatment forms could include usse of steroid injections, physiotherapy, heat and infrared therapy.. Some may even need surgeries.. You need to be evaluated first to see the extent of injuries, then the best treatment options can be suggested.. Consult a spine surgeon.. Or you may take an opinion from one of the spine surgeons available on line.. They are available on this website too...