work accident

hi there.
my name is paul.
last friday i got up for work and had a bit of a stiff neck.
i went to work and on arrival told my supervisor of the problem and asked to be put on light dutys.
he did put me on light dutys but a couple of hours in to our shift one of out colleagues was suspended for reasons unknown.
then the manager told the superviser to shift the staff around to compensate for the suspended colleague and the manager took over my job.
and put me on a job that includes lifting heavy baskets of tomatoes. about 20 25 kgs each.
i told the superviser before i lifted the baskets that i shouldnt be on that job as my neck was stiff and the manager was aware of this and they just said it was a nightmare as we where short staffed.
i then lifted a basket of tomatoes up and the ligerments in my back gave way and was in agony and still is in a lot of pain now.

i went to the emergency doctor on the friday as i couldnt get an appointment with my usual doctor. who told me just to take some <I brufen>over the weekend i took the i brufen but they where not working so i got an appointmen to see the doctor on the monday and he prescribed <diazepam 2 mg and diflofenac 50mg> and told me to just self sertify <ssp>
after taking them i started to feel a little improvment but then on wednesday my back gave way again  as it wasnt able to take my full waight just trying to stand up.
so i went back to the doctor on the thursday by this time in huge amounts of pain and was prescribed<methocarbamol 750mg>
he gave me a sick note that lasts till next thursday.
iv filled the accident book in just after doing it and was interviewed by the hr dep and told i will have to take responsibility for it.
do you think i have a claim againt them ?
best regards
paul johnson