I believe Montague is over thinking this a bit. If WW hadn't trained chest heavy in years what can you expect but pain, though it may not be all due to lactic buildup.
One way to get the body back to normal is to do the same exercise that caused pain in the first place. Benches cause pain, than the next day do light, high rep benches with the bar(or extra light DB's) only. Put a warming agent on the selected body part, along with a heavy sweat shirt. Want to increase the circulation in the selected area.
Want a higher potential for lactic acid than do SS's, Tri set's, Quad set's, Pre-exhausr, etc. With short rest periods between sets, like 45 seconds. 8 to 10 (or above) sets. If that makes you extra happy, that is. Good Luck.