Severe Burning Muscle Pain during Exercise

Hello!  Thanks in advance for taking the time to read this post.

When I was a kid, I was very active and in excellent shape.  I started smoking in college and spent many years with little/no physical activity.  Now 36, I've quit smoking and am more active, but I am having a severe burning sensation in my arm muscles when I exercise, more in the upper arm, but also in the lower arm, which seems too strong simply to be lactic acid burn (I think people would stop exercising if they hurt this much).

Let me give more background.  As long as 10 years ago, I would feel this arm pain on the occasions that I did heavy lifting or played tennis.  The burning pain was fairly strong, but it was not crippling, and it generally went away in a couple hours.  Faster, it seems, if I took ibuprofen.  In the last 2 years, I have started rock climbing, and there have been times after I stopped climbing, I would be nearly crying, the burning pain in my arms was so severe.  Again ibuprofen seems to help alleviate the pain, and there is little/no apparent after-effect the next day.  After a while - maybe 6 months of climbing, the pain no longer came, and I could climb for a couple hours comfortably, or if there was pain, it was relatively mild and manageable.  However, lately (and see the next paragraph), the pain has become severe again and is curtailing my exercise.

Important maybe to note, in the past 5 months, I have been seeing a chiropractor, and he has helped me with several old nagging pains in my neck, shoulder and hip.  For the first 4 months of treatment, he forbade me from climbing.  Now that I'm free to climb again, I am experiencing the most severe burning pains in my arms again.  My chiropractor thinks that it may be my nerves are sending the wrong information to my muscles.

I'm looking for A) additional opinions; B) recommendations for treatment.

Thanks!