I agree with the above good doctor's advice, you need to be in some sort of physical therapy to strenghten and improve flexibility of muscles related to your spine. Also, if your accident was fairly recent, you need to rest a lot, so not being able to get out of bed is your body trying to tell you something. You also need to be on some sort of medicine, either pain killers or antispasmodics, to help control the discomfort you are experiencing in your back, since the shots are not enough. Anytime you hurt your spine, it's going to be painful for several months, so as the doc above posted, you need to see your specialist about all this.
Thank you for your question. Although without being able to examine you I can not offer you the specific advice on diagnosis and treatment that you need, but I would try to provide you some relevant information about your health concern.
I do sympathize with your vertebra injury concern. Although I am not sure that how much recovery you have gained, but it is quite essential that you make an arrangement to meet with a physiotherapist or chiropractor who may advice you some exercises to gain muscle strength. In addition, spinal nerves decompression & electrical nerve stimulation may help in recovering from certain extent. If you suffer continuous muscle weakness or notice further atrophy of leg muscles, please arrange an appointment with a neurologist right away who will evaluate the possibilities here and can provide you an appropriate treatment. Hope this information proves helpful to you. Take Care & Regards!!!