Weakness And Twitching In Tricep, Anxiety, Taking Ibuprofen, Had Acupuncture. Want Reassurance.

Question : I have been weight training for quite some time, and I am very focused on fitness. On Saturday, December 31, around 11:00 a.m. I was doing a routine lateral pulldown on the machine at the gym. On one of my final reps, I felt a mild strain or pull just to the left of my spine (just near, or right under, my left scapular) as I was pulling down. There was no immediate pain after I completed the exercise, just a residual dull "ache" from the mild strain. It was gone relatively soon after. That evening around 5:00 pm, I started feeling twitching in my left tricep and left pectoral muscles (in the pec, the twitching was near the outter top portion of the pec). The next morning I woke up with continued twitching in the same areas and I had a feeling of a "knot" in the place where I felt the mild strain the day before. I also felt some weakness in my tricep. I saw a massage therapist who worked on the "knot," but there wasn't much relief from the dullness in that area. The twitching continued and has continued all this past week (although it has gotten much less frequent), and I have noticed that at this point, I have lost almost all of my strength in the left tricep and the left pectoral muscles (but the muscles are still working, and I don't feel numbness or anything like that). I used to be able to do 100 pushups with no problem, and now I can't even do one because my left side is so weak. The weakness started on the day after the initial strain and has continued all week with really no improvement. All week t has been a mild dull "ache" off an on in several areas: the area under or next to my scapula where I initially felt the pull, in my left armpit, and sometimes in my left forearm (but the forearm has been recent in the last day or two). Most of the dullness has been off or on where I initially felt the strain or in my left armpit where my pectoral muscle starts. I have a lot of anxiety over this, so please don't scare me. I couldn't get into a sports med doc until next week. This past week, I have been resting and taking ibuprofin. I also had a couple of acupuncture treatments. There is not really any pain, other than the off and on mild dull "ache" which isn't really bothersome. The twitching has subsided for the most part, but is still there in the pec and tricep off an on (and sometimes even in the left lat muscle). I just want some reassurance that all will be ok, even if it means some physical therapy, etc. My major concern is that I am already feeling a difference in the mass of my left tricep as opposed to my right tricep. The muscle in my left tricep is no longer as firm or big as my right tricep (and they were once pretty much equal).