BC post treatment pain

I was treated for Stage 2 breast cancer last year with AC/Taxol followed by a mastectomy. As crappy as chemo was, I was shocked at how quickly my body recovered. The Taxol caused neuropathy and joint pain, but most of that was gone within a month of finishing treatment. Within 4 months, all of my symptoms were gone and I felt completely recovered physically. The only thing that isn't healed is the cording in my arm from the surgery and a mild seroma (fluid build up on my side). I was excited to get back to work doing a physical job where I'm on my feet all day, and I thought I'd be fine because I wasn't feeling any fatigue and was able to do everything I could before cancer treatment. After being back at work for a couple months, I'm finding that at the end of every day, I'm as sore and tired as I would normally be after hiking a difficult mountain. Not winded, just sore from head to toe. I take baths with epsom salts everyday, but they don't seem to do much. At first, I thought I just needed to get back in shape, but after 2 months of absolutely no change, I'm wondering if my body isn't as recovered as I thought it was. I keep waiting for my body to build up strength, since I'm doing the same tasks everyday, but so far no change. I'm only 34 and many of my co-workers who are in their 40s and 50s seem to be able to handle the physical work much better than me, even after I cut down my hours. One thing that's been so frustrating through treatment is the vagueness from doctors about what my symptoms "might" be. I have no clue if what I'm experiencing is just a normal body being tired after a long day, or a weakened body that isn't as able to heal as well as it used to. I also wonder if my brain is so used to feeling sick that it's tricking me into thinking I'm not strong anymore. If I understood it better, I could cope better and maybe learn how to improve my strength. Has anyone else dealt with surprise soreness or fatigue after they thought it had gone away?