In order for us to really help you, it would be good to know what the exercises are and how frequently you have been doing them.
As others have already said, what type of pain are you experiencing? A little muscle soreness post-workout is acceptable, but more acute pain could indicate muscle strain, commonly caused by overdoing the loading of the exercises, with too heavy weight, too many sets an repetitions or all 3. If you provided this info we may be able to tell if you are overdoing it. Also do you see the trainer regularly to review the program? I you have not seen him/her for 8 weeks or even as little as 2 weeks (don’t take this personally!) there is a good change you are doing them wrong. Regular reviews of programs are very important and 8 weeks would definitely be too long to go without one, for any client of any ability level.
Say you are doing everything correctly, but pain is continuing or even getting worse, and the traps just keep tightening up again, you could have compression of the nerves serving the muscles, caused by poor posture, spine vertebra mis-alignment, or even a bulged spinal disk. If this is more like your case, definitely seek medical advice.
It is also possible the exercises given to you aren’t the right ones to correct your particular issue with the traps.
As others have already mentioned, if your issues are caused by lifestyle, it can take as long as 3-12 months to see real improvements. Say you work 40 hours per week typing ad telephoning at a computer desk and have done for 20 years, 2 hours of exercises per week won’t give you much of an improvement. Postural correction is a labour I love for the client and he or she needs to be very dedicated to the cause, making as many lifestyle adjustments as possible to help process along and get themselves out of pain.
I hope this helps you! Good luck!