Yep, you got it. Did the same thing in my late 40's when I used a 4' pry bar to remove dozens of big nails out of very old hard roof rafters. Pain lasted for a long time--over 8 months. Finally knocked it out with a brace, ice and continual high doses of Naproxen.
Second time it happened, it took a steroid shot to get rid of it.
If I were you I'd be taking high doses of Ibuprofen every 4 hrs (600mg or so) every 4 hrs for at least 3 or 4 days to combat it. Ice it frequently.
But, remember, don't get medical advice from a Mercedes forum.

One consequence of my experience is that I don't swing long handled hammers anymore and I use my legs and not arms on tight nuts.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13