hi again -
when you saw your doc what all did he/she do and say about your pains?
X-rays are good for showing broken bones, joint displacements or foreign objects -mainly solid objects. it may show shadows of muscles but will not show if a muscle is enlarged or if there is a tear.
you should have an MRI done as this will show more details relating to muscles, spine, heart, head etc., so it shows a lot more details.
I think you should discuss this with your doctor and have an MRI done - once the films are done then you should take them to a specialist to be viewed properly for a complete diagnosis and treatment plan. An Orthopedic Spine Specialist or Neurosurgeon Spine Specialist {assuming the MRI shows a disc(s) problems} may be the one that you need to see, or a Orthopedic Surgeon that specializes in shoulder/muscle problems.
there could be a number of reasons for the pains and it's hard to say what you need to have done. One thing, it may be beneficial for you to stop any exercising until you have been fully examined and a full diagnosis has been given. they will let you know what type(s) of treatment plan(s) that can be done.
I know this isn't exactly what you were looking for but you can try heat and ice treatments until you get in to see a specialist - heat pad for 20 minutes (on low) 20 minutes nothing then 20 minutes ice pack. you can do this 4-6 times a day. taking ibuprofen will help with any swelling and minor pains but be careful not to exceed 4,000mg a day to avoid damages to liver.
hope this helps more - let us know what you find out - take care - Joy