Never Ending Back Pain Please Advise

I have had a few back problems in the past 3 years, but nothnig very serious, mostly just muscle problems. My problem is that for the past 2 weeks my back has a sharp pain on both sides of my lower spine(lumbar area), and it radiates out about 3-4 inches on each side of the spine. Despite several different streching excersises, hot baths, ice, and a ton of relaxation the pain just will not go away. It's all day long....as soon as I wake, and all the way through the day. My past back pain has not been like this, it just gets very sore, and then goes away. I own a construction company, and put alot of work on my back, but for the past 3 weeks I have only worked on and off due to the current slow is building. Please lend some advice on what is wrong with my back. I will go to a doctor, but what type of doctor would be best, and if any doctors read this could you give some suggestions about what is going on please?